Method and apparatus for video decoding

ABSTRACT

This application relates to a method and apparatus, a storage medium, and a computer device for video encoding and decoding. The video encoding method includes: acquiring a reference frame corresponding to a current frame to be encoded from a video input; determining a sub-pixel interpolation mode, the sub-pixel interpolation mode comprising one of a direct sub-pixel interpolation mode or a sampled sub-pixel interpolation mode; processing the reference frame according to resolution information of the current frame using an interpolation in the sub-pixel interpolation mode, to obtain a corresponding target reference frame; and encoding the current frame according to the target reference frame, to obtain encoded data corresponding to the current frame. By using the foregoing video encoding method, a reference frame corresponding to a current frame to be encoded can be flexibly selected, thereby effectively improving the utilization efficiency of reference frames.

RELATED APPLICATION

This application is a continuation application of the International PCTApplication No. PCT/CN2019/090682, filed with the National IntellectualProperty Administration, PRC on Jun. 11, 2019 which claims priority toChinese Patent Application No. 201810635813.6, entitled “VIDEO ENCODINGMETHOD AND APPARATUS, VIDEO DECODING METHOD AND APPARATUS, STORAGEMEDIUM, AND COMPUTER DEVICE” and filed with the National IntellectualProperty Administration, PRC on Jun. 20, 2018, which are incorporatedherein by reference in their entireties.

FIELD OF THE TECHNOLOGY

This application relates to the field of computer technologies, and inparticular, to a method and apparatus, a video decoding method andapparatus, a storage medium, and a computer device for video encoding.

BACKGROUND OF THE DISCLOSURE

With the development of digital media technologies and computertechnologies, videos are applied to many fields such as mobilecommunication, network monitoring, and network television. With theimprovement of hardware performance and screen resolution, demand forhigh-definition videos is increasing.

With a limited bandwidth, video quality may be poor in some scenarios ifa conventional encoder is used which encodes video framesindiscriminately. For example, during indiscriminate encoding of allvideo frames at a bit rate of 750 kbps, all referenced video frames havethe same resolution, and only reference frames with the same resolutioncan be referenced for the video frames, resulting in low utilizationefficiency of reference frames and an inflexible reference relationship.

SUMMARY

Embodiments of this application provide a method and apparatus, a videodecoding method and apparatus, a storage medium, and a computer devicefor video encoding, so that a current frame to be encoded from a videoinput may be encoded with reference to a specific reference frame ifreference frames have different resolutions, the utilization efficiencyof reference frames can be improved, a reference relationship betweenvideo frames becomes more flexible, and the technical problem that theutilization efficiency of reference frames is not high because all videoframes are encoded indiscriminately in the related art can be resolved.

A video encoding method is provided, the method being performed by acomputer device, the method including:

acquiring a reference frame corresponding to a current frame to beencoded from a video input;

determining a sub-pixel interpolation mode, the sub-pixel interpolationmode comprising one of a direct sub-pixel interpolation mode and asampled sub-pixel interpolation mode;

processing the reference frame according to resolution information ofthe current frame using the sub-pixel interpolation mode, to obtain acorresponding target reference frame; and

encoding the current frame according to the target reference frame, toobtain encoded data corresponding to the current frame.

A video encoding apparatus is provided, the apparatus being applied to acomputer device, the apparatus including:

a reference frame acquisition module, configured to acquire a referenceframe corresponding to a current frame to be encoded from a video input;

a sub-pixel interpolation mode determination module, configured todetermine a sub-pixel interpolation mode, the sub-pixel interpolationmode comprising one of a direct sub-pixel interpolation mode and asampled sub-pixel interpolation mode;

a target reference frame determination module, configured to process thereference frame according to resolution information of the current frameby using the sub-pixel interpolation mode, to obtain a correspondingtarget reference frame; and

an encoded data obtaining module, configured to encode the current frameaccording to the target reference frame, to obtain encoded datacorresponding to the current frame.

A computer-readable storage medium is provided, storing a computerprogram, and the computer program, when being executed by a processor,causing the processor to perform the steps of the foregoing videoencoding method.

A computer device is provided, including a memory and a processor, thememory storing a computer program, and the computer program, when beingexecuted by the processor, causing the processor to perform the steps ofthe foregoing video encoding method.

By using the foregoing video encoding method and apparatus, storagemedium, and computer device, after a reference frame corresponding to acurrent frame is acquired, a sub-pixel interpolation mode of thereference frame may be determined. Then based on the resolution of thereference frame, the reference frame is processed and the resolution ofthe reference frame may be adjusted to obtain a target reference frame.As such, even if the resolution of the reference frame is different fromthat of the current frame, the reference frame may still be used as areference frame for the current frame after the adjustment. The currentframe is encoded according to the obtained target reference frame,thereby improving the utilization efficiency of reference frames, sothat the accuracy of inter prediction can be improved, a predictionresidual can be reduced, and the quality of an encoded image can beimproved.

A video decoding method is provided, the method being performed by acomputer device, the method including:

acquiring encoded data corresponding to a current frame to be decodedfrom a video input;

acquiring a reference frame corresponding to the current frame;

determining a sub-pixel interpolation mode, the sub-pixel interpolationmode comprising one of a direct sub-pixel interpolation mode and asampled sub-pixel interpolation mode;

processing the reference frame according to resolution information ofthe current frame by using the sub-pixel interpolation mode, to obtain acorresponding target reference frame; and

decoding the encoded data according to the target reference frame, toobtain a reconstructed video frame corresponding to the current frame.

A video decoding apparatus is provided, the apparatus being applied to acomputer device, the apparatus including:

an encoded data acquisition module, configured to acquire encoded datacorresponding to a current frame to be decoded from a video input;

a reference frame acquisition module, configured to acquire a referenceframe corresponding to the current frame;

a sub-pixel interpolation mode determination module, configured todetermine a sub-pixel interpolation mode, the sub-pixel interpolationmode comprising one of a direct sub-pixel interpolation mode and asampled sub-pixel interpolation mode;

a target reference frame determination module, configured to process thereference frame according to resolution information of the current frameby using the sub-pixel interpolation mode, to obtain a correspondingtarget reference frame; and

a reconstructed video frame obtaining module, configured to decode theencoded data according to the target reference frame, to obtain areconstructed video frame corresponding to the current frame.

A computer-readable storage medium is provided, storing a computerprogram, and the computer program, when being executed by a processor,causing the processor to perform the steps of the foregoing videodecoding method.

A computer device is provided, including a memory and a processor, thememory storing a computer program, and the computer program, when beingexecuted by the processor, causing the processor to perform the steps ofthe foregoing video decoding method.

By using the foregoing video decoding method and apparatus, storagemedium, and computer device, after encoded data corresponding to acurrent frame to be decoded and a reference frame corresponding to thecurrent frame are acquired, a sub-pixel interpolation mode of thereference frame may be determined. Then based on the resolution of thereference frame, the reference frame is processed and the resolution ofthe reference frame may be adjusted to obtain a target reference frame.As such, even if the resolution of the reference frame is different fromthat of the current frame, the reference frame may still be used as areference frame for the current frame after the adjustment. The currentframe is decoded according to the obtained target reference frame,thereby improving the utilization efficiency of reference frames, sothat the accuracy of inter prediction can be improved, a predictionresidual can be reduced, and the quality of an encoded image can beimproved. In this application, inter prediction may also be referred toas inter-frame prediction.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram of an exemplary application environment of a videoencoding method according to an embodiment.

FIG. 2 is a schematic flowchart of a video encoding method according toan embodiment.

FIG. 3 is a schematic framework diagram of a video encoding frameworkaccording to an embodiment.

FIG. 4 is a schematic diagram of a hybrid-resolution encoding frameworkaccording to an embodiment.

FIG. 5 is a schematic diagram of encoding an input video frame withdifferent resolutions according to an embodiment.

FIG. 6(1) is a schematic diagram of performing pixel interpolation withpixel precision of 1/2 on a reference frame according to an embodiment.

FIG. 6(2) is a schematic diagram of performing pixel interpolation withpixel precision of 1/4 on a reference frame according to an embodiment.

FIG. 7 is a schematic flowchart of processing a reference frameaccording to resolution information of a video frame by using asub-pixel interpolation to obtain a corresponding target reference frameaccording to an embodiment.

FIG. 8 is a schematic flowchart of processing a reference frameaccording to resolution information of a video frame and motionestimation pixel precision by using a sub-pixel interpolation to obtaina corresponding target reference frame according to an embodiment.

FIG. 9 is a schematic flowchart of processing a reference frameaccording to resolution information of a video frame and motionestimation pixel precision by using a sub-pixel interpolation to obtaina corresponding target reference frame according to another embodiment.

FIG. 10 is a schematic flowchart of processing a reference frameaccording to resolution information of a video frame and motionestimation pixel precision by using a sub-pixel interpolation to obtaina corresponding target reference frame according to still anotherembodiment.

FIG. 11 is a schematic flowchart of encoding a video frame according toa target reference frame, to obtain encoded data corresponding to thevideo frame according to an embodiment.

FIG. 12 is a schematic flowchart of encoding a video frame according toa target reference frame, to obtain encoded data corresponding to thevideo frame according to another embodiment.

FIG. 13 is a schematic flowchart of a video decoding method according toan embodiment.

FIG. 14 is a schematic diagram of a hybrid-resolution decoding frameworkaccording to an embodiment.

FIG. 15 is a schematic flowchart of processing a reference frameaccording to resolution information of a current frame by using asub-pixel interpolation to obtain a corresponding target reference frameaccording to an embodiment.

FIG. 16 is a schematic flowchart of decoding encoded data according to atarget reference frame, to obtain a reconstructed video framecorresponding to a current video frame according to an embodiment.

FIG. 17 is a structural block diagram of a video encoding apparatusaccording to an embodiment.

FIG. 18 is a structural block diagram of a video decoding apparatusaccording to an embodiment.

FIG. 19 is a structural block diagram of a computer device according toan embodiment.

FIG. 20 is a structural block diagram of a computer device according toan embodiment.

DESCRIPTION OF EMBODIMENTS

To make the objectives, technical solutions, and advantages of thisapplication clearer, the following further describes this application indetail with reference to the accompanying drawings and the embodiments.It is to be understood that the specific embodiments described hereinare only used to describe this application, instead of limiting thisapplication.

FIG. 1 is a diagram of an application environment of a video encodingmethod according to an embodiment. Referring to FIG. 1, the videoencoding method is applied to a video encoding system. The videoencoding system includes a terminal 110 and a server 120. The terminal110 is connected to the server 120 by a network. The terminal 110 maybe, but is not limited to, a desktop terminal or a mobile terminal, andthe mobile terminal may be specifically at least one of a mobile phone,a tablet computer, a notebook computer, and the like, there is nolimitation imposed in this application. The server 120 may beimplemented by using an independent server or a server cluster thatincludes a plurality of servers.

The video encoding method and the video decoding method may beimplemented in the terminal 110 or the server 120. The terminal 110 mayencode a current frame by using the video encoding method, and thentransmit the encoded video frame to the server 120, or receive encodeddata from the server 120, decode the encoded data by using the videodecoding method, and then generate a reconstructed video frame. Theserver 120 may perform transcoding on a code stream during storage. Inthis case, the video encoding method is completed on the server. If theserver 120 needs to decode the code stream, the video decoding method iscompleted on the server. It may be understood that an encoding end and adecoding end may be the same end or different ends. The computer device,for example, a terminal or a server, may be an encoding end or adecoding end, or both an encoding end and a decoding end.

Referring to FIG. 1, the terminal 110 or the server 120 may performvideo encoding by using an encoder or video decoding by using a decoder.The terminal 110 or the server 120 may also perform video encoding byusing a processor running a video encoding program or video decoding byusing a processor running a video decoding program. After receiving,through an input interface, encoded data transmitted by the terminal110, the server 120 may directly transfer the encoded data to theprocessor for decoding, or may store the encoded data in a database forsubsequent decoding. After obtaining encoded data by encoding anoriginal video frame by the processor, the server 120 may directlytransmit the encoded data to the terminal 110 through an outputinterface, or may store the encoded data in a database for subsequenttransfer.

In a possible application scenario, the video encoding method and thevideo decoding method provided in this application may be applied to anapplication having a video call function. The application may be asocial application or an instant messaging application. During a videocall between two terminals installed with embodiments of theapplication, a first terminal acquires a video frame by using a camera,encodes the video frame by using a video encoding function of anapplication, to obtain encoded data, and transmits the encoded data to abackground server of the application. The background server forwards theencoded data to a second terminal. After receiving the encoded data, thesecond terminal decodes the encoded data by using a video decodingfunction of the application, and performs reconstruction to obtain avideo frame, so as to display the video frame. Similarly, the secondterminal may transmit the encoded data obtained through encoding to thefirst terminal by using the background server, and the first terminalperforms decoding and display, thereby implementing a video call betweenthe two parties.

In another possible application scenario, the video encoding method andthe video decoding method provided in this application may be applied toan application having a video playback function. The application may bea video live streaming application, a short video application or a videoplayback application. A terminal installed with embodiments of theapplication may acquire a video frame by using a camera, encode thevideo frame by using a video encoding function of the application, toobtain encoded data, and transmit the encoded data to a backgroundserver of the application. If another terminal requests to watch thevideo, the background server transmits encoded data of the video to theother terminal. An application on the other terminal decodes the encodeddata, to play the video.

Certainly, the foregoing several possible application scenarios are onlyused for exemplary description. The video encoding method and videodecoding method provided in the embodiments of this application mayfurther be applied to any scenarios that require video encoding anddecoding. This is not limited in the embodiments of this application.

As shown in FIG. 2, in an embodiment, a video encoding method isprovided. This embodiment is described by using an example in which themethod is applied to the terminal 110 or the server 120 in FIG. 1.Referring to FIG. 2, the video encoding method specifically includes thefollowing steps.

S202: Acquire a reference frame corresponding to a current frame to beencoded from a video input.

The current frame may be a video frame acquired in real time or a videoframe corresponding to a stored video. The current frame may be an inputvideo frame in an input video frame sequence. The current frame may bealternatively a video frame obtained after processing an input videoframe in an input video frame sequence by using a correspondingprocessing mode. After an encoding end processes the input video frameby using the corresponding processing mode, a resolution of the obtainedvideo frame to be encoded is less than a resolution of the originalinput video frame. For example, down-sampling processing may beperformed on the input video frame according to a corresponding samplingratio to obtain the current frame.

Specifically, the encoding end may determine a processing mode of aninput video frame, and process the input video frame according to theprocessing mode of the input video frame, to obtain the current frame.The processing mode includes a down-sampling processing mode and afull-resolution processing mode. In the down-sampling processing mode,an input video frame is down-sampled to obtain the current frame, andthe obtained video to be encoded frame is encoded. A down-sampling modein the down-sampling processing mode may be customized as required,which further includes vertical down-sampling, horizontal down-sampling,and vertical and horizontal down-sampling. Down-sampling may beperformed by using algorithms such as a direct average algorithm, afilter algorithm, a bicubic interpolation algorithm, and a bilinearinterpolation algorithm. In the full-resolution processing mode, aninput video frame is directly used as the current frame, and the currentframe is directly encoded based on an original resolution of the inputvideo frame.

In an embodiment, the video encoding framework is shown in FIG. 3, andincludes a constant-resolution encoding framework and ahybrid-resolution encoding framework. The encoding end may encode aninput video frame sequence by using the hybrid-resolution encodingframework or the constant-resolution encoding framework. If the inputvideo frame sequence is encoded using the constant-resolution encodingframework, each input video frame in the input video frame sequence isencoded by using a full-resolution processing mode. Theconstant-resolution encoding framework may be a HEVC encoding framework,a H.265 encoding framework or the like. If the hybrid-resolutionencoding framework shown in FIG. 4 is used to encode an input videoframe sequence, each input video frame in the input video frame sequencemay be encoded by using either the full-resolution processing mode orthe down-sampling processing mode. For example, referring to FIG. 5, inthe input video frame sequence, the N^(th) input video frame is encodedusing the full-resolution processing mode, the (N+1)^(th) input videoframe is encoded using the down-sampling processing mode, and the(N+2)^(th) input video frame is encoded by using the full-resolutionprocessing mode.

FIG. 4 is a schematic diagram of a hybrid-resolution encoding frameworkaccording to an embodiment. Referring to FIG. 4, the encoder encodeseach frame of the input video in the acquired input video frame sequenceto obtain corresponding encoded data, and stores or transmits theencoded data or stores and transmits the encoded data by using astorage/transmission unit 422. At a processing mode decision unit 402,processing mode decision may be performed on an input video frame, toobtain a processing mode corresponding to the input video frame. At afirst processing unit 404, the input video frame may be processedaccording to the processing mode obtained by the processing modedecision unit 402, to obtain a current frame to be encoded from a videoinput. At a first prediction unit 406, at a resolution of the currentframe, it may be determined to perform intra-frame prediction orinter-frame prediction on each encoded block in the current frame, animage value of a reference block of an encoded block is obtained toobtain a corresponding predicted value and a corresponding motionvector, and subtraction is performed on an actual value of the encodedblock and the predicted value to obtain a prediction residual. The valueof the motion vector may be a displacement of the encoded block relativeto the reference block. At a transformation unit 408, the predictionresidual and data of the motion vector are transformed from a spatialdomain to a frequency domain, and a transformation coefficient may beencoded. A transformation method may include discrete Fourier transform,discrete cosine transform, and the like. At a quantization unit 410, thetransformed data is mapped into another value. For example, thetransformed data is divided by a quantization step to obtain arelatively small value. A quantization parameter is a sequence numbercorresponding to the quantization step, and a corresponding quantizationstep may be found according to the quantization parameter. A smallquantization parameter indicates reservation of most details of an imageframe and a high corresponding bit rate. A large quantization parameterindicates a low corresponding bit rate, relatively large imagedistortion, and low image quality. An entropy encoding unit 420 isconfigured to perform entropy encoding. The entropy encoding is a dataencoding mode according to an entropy principle without loss of anyinformation, and particular information can be expressed by using arelatively small quantity of characters. An entropy encoding method maybe, for example, a Shannon encoding method or a Huffman encoding method.

A first inverse quantization unit 412, a first inverse transformationunit 414, a first reconstruction unit 416, and a first referenceinformation adaptation unit 418 are units corresponding to pathreconstruction. The units for path reconstruction are used to performframe reconstruction to obtain a reference frame, so that referenceframes can be kept consistent in encoding and decoding. Steps performedby the first inverse quantization unit 412 are an inverse process ofquantization. Steps performed by the first inverse transformation unit414 are an inverse process of transformation performed by thetransformation unit 408. The first reconstruction unit 416 is configuredto add residual data obtained through inverse transformation topredicted data to obtain a reconstructed reference frame. The firstreference information adaptation unit 418 is configured to performadaptive processing on at least one piece of reference information suchas a reconstructed reference frame, position information correspondingto each encoded block in the current frame, position informationcorresponding to each reference block in the reference frame, and amotion vector at a resolution of the current frame, to enable the firstprediction unit 406 to perform prediction according to the referenceinformation obtained after the adaptive processing.

In an embodiment, the encoding end may further add encoding frameworkinformation corresponding to an encoding framework used in encoding ofan input video frame sequence to encoded data corresponding to the inputvideo frame sequence. An addition position of the encoding frameworkinformation in the encoded data may be determined according to an effectrange of the encoding framework. Specifically, the encoding frameworkinformation may be added to sequence header information corresponding tothe encoded data, and is used for informing a decoding end of anencoding framework used in encoding of each input video frame in theinput video frame sequence corresponding to the current encoded data,each input video frame in the input video frame sequence using the sameencoding framework. For example, if a flag bit Sequence_Mix_Flag usedfor determining the used encoding framework in the sequence headerinformation of the encoded data is 0, it indicates that all the inputvideo frames in the input video frame sequence are encoded by using theconstant-resolution encoding framework. If Sequence_Mix_Flag is 1, itindicates that all the input video frames in the input video framesequence are encoded by using an adaptive-resolution encoding framework,so that the decoding end may decode the encoded data according to adecoding framework corresponding to the encoding framework to obtain areconstructed video frame sequence.

In an embodiment, a processing mode corresponding to the input videoframe may be set according to practical considerations. For example, aprocessing parameter corresponding to the input video frame may beacquired, and a corresponding processing mode is obtained according tothe processing parameter. The processing parameter is a parameter usedfor determining a processing mode. A specific processing mode may be setand adjusted as required. For example, the processing parameter mayinclude current encoding information and/or image feature informationcorresponding to the input video frame. The processing mode may beadjusted dynamically for a video frame sequence.

In an embodiment, the encoding end may obtain a processing modecorresponding to the input video frame according to at least one of thecurrent encoding information and the image feature informationcorresponding to the input video frame. The current encoding informationis obtained video compression parameter information such as one or moreof a frame type, a motion vector, a quantization parameter, a videosource, a bit rate, a frame rate, and a resolution of a video duringencoding. The image feature information is information related to imagecontent, and includes one or more of image motion information and imagetexture information, for example, an edge. The current encodinginformation and the image feature information reflect a scene, detailcomplexity, motion intensity or the like that corresponds to a videoframe. For example, a motion scene may be determined by using one ormore of a motion vector, a quantization parameter, and a bit rate. Alarge quantization parameter usually indicates intense motion, and alarge motion vector indicates that an image scene is a large motionscene.

The encoding end may also perform determination according to a ratio ofa bit rate of an encoded I frame (Intra-coded frame) to that of anencoded P frame (Predicted frame) or a ratio of the bit rate of theencoded I frame to that of an encoded B frame (Bi-directional predictedframe). If the proportion exceeds a first preset threshold, it isdetermined that an image is a still image. If the proportion is lessthan a second preset threshold, it may be determined that an image is anintense motion image. Alternatively, a target object is directly trackedaccording to image content, and it is determined according to a motionspeed of the target object whether a scene is a large motion scene. Afixed bit rate indicates a fixed amount of information that can beexpressed. For an intense motion scene, an amount of information in atime domain is large, and accordingly, a bit rate that can be used forexpressing information in a spatial domain is small. Therefore, arelatively desirable image quality effect can be achieved by using a lowresolution, and a down-sampling mode is more likely to be selected forencoding. A picture switching scenario may be determined according to aframe prediction type, or an encoding mode that is likely to be selectedmay be determined according to the impact of the frame prediction typeon other frames. For example, an I frame is usually the first frame orthere is picture switching, and the quality of the I frame affects thequality of a subsequent P frame or B frame. Therefore, compared withinter prediction, a full resolution encoding is more likely to beselected for intra prediction, to ensure image quality. The P frame maybe used as the reference frame of the B frame, and image quality of theP frame affects image quality of the subsequent B frame. Therefore, afull resolution encoding is more likely to be selected for encoding withthe P frame compared with encoding with the B frame.

Texture complexity of a current frame to be encoded is determinedaccording to the image feature information, for example, image textureinformation. If texture is complex and includes a large number ofdetails, there is a large amount of image spatial domain information. Ifdown-sampling is performed, a relatively large amount of detailinformation may be lost due to the down-sampling, and video quality isaffected. Therefore, a full resolution is more likely to be selected fora current video frame having a complex texture for encoding comparedwith that having simple texture.

In an embodiment, the encoding end may obtain a processing modecorresponding to the input video frame according to a value relationshipbetween a current quantization parameter corresponding to the inputvideo frame and a quantization parameter threshold. If the currentquantization parameter is greater than the quantization parameterthreshold, it is determined that the processing mode is a down-samplingmode, or otherwise, it is determined that the processing mode is afull-resolution mode. The quantization parameter threshold may beobtained according to a proportion of intra-frame encoded blocks in anencoded forward encoding video frame before an input video frame, and acorrespondence between a proportion of intra-frame prediction blocks anda quantization parameter threshold may be preset, so that after aproportion of intra-frame prediction blocks in a current frame isdetermined, a quantization parameter threshold corresponding to theproportion of intra-frame prediction blocks in the current frame may bedetermined according to the correspondence. For constant-quantizationparameter encoding, the current quantization parameter may be acorresponding constant quantization parameter value. For constant-bitrate encoding, a current quantization parameter corresponding to aninput video frame may be calculated according to a bit rate controlmodel. Alternatively, a quantization parameter corresponding to areference frame may be used as a current quantization parametercorresponding to the input video frame. In this embodiment of thepresent application, a larger current quantization parameter usuallyindicates higher motion intensity, and the down-sampling mode is morelikely to be selected for encoding in an intense motion scenario.

In an embodiment, the encoding end may further calculate a proportion ofencoded blocks of a target prediction type in a forward encoding videoframe corresponding to an input video frame, and a processing modecorresponding to the input video frame is determined according to theproportion.

Specifically, an encoded block of a prediction type is an encoded blockcorresponding to a frame prediction type. A proportion of the targetprediction type may a proportion corresponding to intra-frame encodedblocks, or a proportion corresponding to inter-frame encoded blocks, orboth. The proportion of the encoded blocks of the target prediction typein the forward encoding video frame corresponding to the input videoframe may be a proportion of the encoded blocks of the target predictiontype to encoded blocks of other prediction types or may be a proportionof encoded blocks of the type to a total quantity of encoded blocks.This may be specifically set as required. For example, a first quantityof intra-frame encoded blocks in the forward encoding video frame and asecond quantity of inter-frame encoded blocks in the forward encodingvideo frame may be acquired. A proportion of the intra-frame encodedblocks to the inter-frame encoded blocks is calculated according to thefirst quantity and the second quantity. Alternatively, a third quantityof all encoded blocks in the forward encoding video frame is calculated,and a proportion of the intra-frame encoded blocks to a third dataamount is calculated according to the first quantity and the thirdquantity. A proportion of the inter-frame encoded blocks to the thirddata amount may further be calculated according to the second quantityand the third quantity.

The forward encoding video frame is an encoded video frame encodedbefore a current frame from an input video is encoded. A plurality ofacquired forward encoding video frames may be customized. For example,the forward encoding video frame may be one previous encoded video frameof the input video frame, or the forward encoding video frame may bethree previous encoded video frames of the input video frame. After aproportion corresponding to encoded blocks of a target prediction typein a forward encoding video frame is calculated, a processing modecorresponding to the input video frame is determined according to thecalculated proportion. If a plurality of forward encoding video framesare acquired, corresponding proportions of encoded blocks of differenttypes in each forward encoding video frame may be calculated, weightedcalculation is performed on the proportions to obtain a totalproportion, and a target processing mode corresponding to the inputvideo frame is then determined according to the total proportion and apreset threshold. A weight corresponding to the forward encoding videoframe may be inversely correlated to an encoding distance between theforward encoding video frame and the input video frame.

In an embodiment, the encoding end may calculate a ratio of intra-frameencoded blocks in the forward encoding video frame. If the ratio isgreater than a target threshold, it is determined that the processingmode is a down-sampling processing mode.

For the ratio corresponding to the intra-frame encoded blocks, if theratio is greater than the target threshold, it may be determined thatthe target processing mode corresponding to the input video frame is adown-sampling resolution mode, or otherwise, it is determined that thetarget processing mode corresponding to the video frame is afull-resolution mode. For example, if the ratio is greater than thetarget threshold, it is determined that the processing modecorresponding to the input video frame is a down-sampling resolutionmode, or otherwise, it is determined that the target processing modecorresponding to the video frame is a full-resolution mode.

In this embodiment of the present application, if a ratio of intra-frameencoded blocks is large, it indicates that the video is relativelycomplex or there is relatively low correlation between video frames.Therefore, the obtained prediction residual is relatively large.Therefore, the down-sampling processing mode is more likely to be usedfor encoding, thereby reducing an amount of encoded data.

The target threshold may be determined according to a processing mode ofa reference frame corresponding to the current frame from an inputvideo. If the processing mode of the reference frame corresponding tothe current frame is a down-sampling mode, the encoder may select afirst preset threshold T1, and use the first preset threshold T1 as thetarget threshold. Similarly, if the processing mode of the referenceframe corresponding to the current frame is a full-resolution mode, theencoder may select a second preset threshold T2, and use the secondpreset threshold T2 as the target threshold. Further, after selectingthe target threshold according to resolution information of thereference frame corresponding to the current video frame, the encoderdetermines a processing mode of the current video frame according to thetarget threshold and the ratio of intra-frame encoded blocks in theforward encoding video frame. If the ratio of intra-frame encoded blocksin the forward encoding video frame is greater than the targetthreshold, it is determined that the processing mode corresponding tothe input video frame is the down-sampling processing mode.

In an embodiment, the second preset threshold is greater than the firstpreset threshold. In this case, if the processing mode corresponding tothe reference frame is a full-resolution processing mode, thefull-resolution processing mode is more likely to be used for the inputvideo frame. If the processing mode corresponding to the reference frameis a down-sampling processing mode, the down-sampling processing mode ismore likely to be used for the input video frame.

In an embodiment, if an adaptive-resolution encoding framework is usedto encode the input video frame, the encoding end may further addprocessing mode information corresponding to a processing mode used inencoding of the input video frame to the encoded data corresponding tothe input video frame. Specifically, the processing mode information maybe added to frame header information corresponding to the encoded data,and is used for informing the decoding end of a processing mode used inencoding of the input video frame corresponding to the current encodeddata. For example, if a flag bit Frame_Resolution_Flag used fordetermining a processing mode in the frame header information of theencoded data is 0, it indicates that the input video frame is encoded byusing the full-resolution processing mode. Or if Frame_Resolution_Flagis 1, it indicates that the input video frame is encoded by using thedown-sampling processing mode. The decoding end may decode the encodeddata by using the corresponding processing mode to obtain areconstructed video frame.

In an embodiment, the encoding end may further acquire a processingparameter corresponding to the input video frame, and determine aprocessing mode corresponding to the input video frame according to theprocessing parameter. If the processing parameter cannot recur in adecoding process, processing mode information corresponding to theprocessing mode is added to the encoded data corresponding to the inputvideo frame.

Specifically, for example, the processing parameter may include at leastone of image encoding information and image feature informationcorresponding to the input video frame. Processing parameter cannotrecur in the decoding process meaning that the processing parametercannot be obtained or generated in the decoding process. For example, ifthe processing parameter is information corresponding to image contentof the input video frame and there is a loss of image information duringan encoding process, the decoded video frame corresponding to the inputvideo frame in the decoding process may be different from the inputvideo frame. Therefore, information corresponding to the image contentof the input video frame may not be obtained or decoded from thedecoding process. That is, the information corresponding to the imagecontent cannot recur in the decoding process. A rate-distortion costneeds to be calculated in the encoding process, and a rate-distortioncost is not calculated in the decoding process. If the processingparameter includes a rate-distortion cost, the processing parametercannot recur in the decoding process. The reconstructed video frameobtained in the encoding process and peak signal to noise ratio (PSNR)information of the input video frame cannot be obtained in the decodingprocess. Therefore, the PSNR information cannot recur in the decodingprocess.

In an embodiment, if the processing parameter can recur at the decodingend, the encoding end may add processing mode information correspondingto the processing mode to the encoded data corresponding to the inputvideo frame or the processing mode information corresponding to theprocessing mode may not be added to the encoded data corresponding tothe input video frame. If the processing mode information correspondingto the processing mode is added to the encoded data corresponding to theinput video frame, the decoding end may read processing mode informationfrom the encoded data, and it is no longer necessary to obtain theprocessing mode according to processed data. If the processing modeinformation corresponding to the processing mode is not added to theencoded data corresponding to the input video frame, a decoding devicedetermines a processing mode according to a processing parameter, sothat the data amount of the encoded data can be reduced.

In an embodiment, if down-sampling processing is performed on an inputvideo frame by using the down-sampling processing mode, to obtain acurrent frame, the encoding end may obtain a specific down-samplingratio according to a capability of a processor of a device such as aterminal or server that performs the video encoding method. A devicehaving a processor with a high processing capability corresponds to alarge down-sampling ratio, and a device having a processor with a lowprocessing capability corresponds to a small down-sampling ratio. Acorrespondence between a processing capability of a processor and adown-sampling ratio may be set. If encoding is required, a processingcapability of a processor is acquired, and a corresponding down-samplingratio is obtained according to the processing capability of theprocessor. For example, it may be set that a down-sampling ratiocorresponding to a 16-bit processor is 1/8, and a down-sampling ratiocorresponding to a 32-bit processor is 1/4.

In an embodiment, the down-sampling ratio may further be obtainedaccording to a frequency or a quantity of times of using an input videoframe as a reference frame. The encoding end may set a correspondencebetween a down-sampling ratio and a frequency or a quantity of times ofusing an input video frame as a reference frame. If the frequency ofusing an input video frame as a reference frame is high or the quantityof times of using an input video frame as a reference frame is large,the down-sampling ratio is large. If the frequency of using an inputvideo frame as a reference frame is low or the quantity of times ofusing an input video frame as a reference frame is small, thedown-sampling ratio is small. For example, if a frequency of using an Iframe as a reference frame is high, a corresponding down-sampling ratiois large, and may be, for example, 1/2. For example, if a frequency ofusing a P frame as a reference frame is low, a correspondingdown-sampling ratio is small, and may be, for example, 1/4. Adown-sampling ratio is obtained according to the frequency or quantityof times of using an input video frame as a reference frame. If thefrequency of using an input video frame as a reference frame is high orthe quantity of times of using an input video frame as a reference frameis large, image quality is relatively high. Therefore, the accuracy ofprediction can be improved, the prediction residual can be reduced, andthe quality of an encoded image can be improved.

In an embodiment, if the encoding end performs down-sampling processingon an input video frame by using the down-sampling processing mode toobtain a current frame, a specific down-sampling method may be obtainedaccording to a capability of a processor of a device such as a terminalor server that performs the video encoding method. A device having aprocessor with a high processing capability corresponds to a complexdown-sampling method, and a device having a processor with a lowprocessing capability corresponds to a simple down-sampling method. Acorrespondence between a processing capability of a processor and adown-sampling method may be set. If encoding is required, a processingcapability of a processor is acquired, and a corresponding down-samplingmethod is obtained according to the processing capability of theprocessor. For example, bicubic interpolation is more complex thanbilinear Interpolation. Therefore, it may be set that a down-samplingmethod corresponding to a 16-bit processor is a bilinear Interpolationmethod and a down-sampling method corresponding to a 32-bit processor isa bicubic interpolation method.

In this embodiment of the present application, during processing of aninput video frame by using the down-sampling processing mode,down-sampling may further be performed according to differentdown-sampling methods or down-sampling ratios, and a processing mode ofan input video frame is more flexible and suitable for the runningenvironment.

In an embodiment, if the encoding end performs down-sampling processingon an input video frame by using the down-sampling processing mode toobtain a current frame, the encoding end may further add at least one ofdown-sampling method information corresponding to a down-sampling methodand down-sampling ratio information corresponding to a down-samplingratio to the encoded data corresponding to the input video frame.

An addition position of the down-sampling method information in theencoded data may be any one of corresponding sequence headerinformation, group header information, and frame header information. Theaddition position of the down-sampling method information in the encodeddata may be determined according to an effect range corresponding to thedown-sampling method. For example, the encoding end may adddown-sampling method information to sequence header information ofencoded data corresponding to an input video frame sequence, indicatingthat during encoding of input video frames in the input video framesequence, down-sampling processing is performed by using thedown-sampling method corresponding to the down-sampling methodinformation, and down-sampling ratios are the same, for example,double-width down-sampling and double-height down-sampling, triple-widthdown-sampling and triple-height down-sampling, or double-widthdown-sampling and triple-height down-sampling. The encoding end may alsoadd down-sampling method information to group header information ofencoded data corresponding to a group of pictures (GOP), indicating thatduring encoding of input video frames in the GOP, down-samplingprocessing is performed by using a down-sampling method corresponding tothe down-sampling method information. The encoding end may further adddown-sampling method information to frame header information of encodeddata corresponding to a video frame, indicating that during encoding ofinput video frames in an input video frame sequence, down-samplingprocessing is performed according to a down-sampling methodcorresponding to the down-sampling method information. For example, aneffect range of a flag bit Down_Sampling_Method that is added to theframe header information and used for determining down-sampling methodinformation is limited on a frame level, indicating that samplingprocessing is performed by using a down-sampling method corresponding todown-sampling method information for an input video frame correspondingto the encoded data.

Similarly, an addition position of the down-sampling ratio informationin the encoded data may be any one of corresponding sequence headerinformation, group header information, and frame header information. Theaddition position of the down-sampling ratio information in the encodeddata may be determined according to an effect range or scopecorresponding to the down-sampling ratio. For example, an effect rangeof a flag bit Down_Sampling_Scale that is added to the frame headerinformation and is used for determining down-sampling ratio informationis limited on a frame level, so that it may be implemented that samplingprocessing is performed by using different down-sampling ratios fordifferent input video frames, to obtain video frames to be encoded withdifferent resolutions. For example, a down-sampling ratio of the firstframe is 1/2, or a down-sampling ratio of the second frame is 1/3.

With a given bit rate, a resolution of a video frame is inverselyproportional to a definition. Therefore, adaptive processing may beperformed on input video frames according to corresponding processingmodes to obtain video frames to be encoded before encoding, so thatencoding quality can be improved, and an image definition can beimproved. In addition, during processing of the input video frame in thedown-sampling processing mode, down-sampling may further be performedaccording to different down-sampling methods and down-sampling ratios,and a processing mode of an input video frame is more flexible.

The reference frame is a video frame that needs to be referenced duringencoding of the current frame. The reference frame is a video frameobtained by reconstructing encoded data corresponding to a video framethat can be used as a reference frame. According to differentinter-frame prediction types, the reference frame corresponding to acurrent video frame to be encoded may be a forward reference frame or abidirectional reference frame, and there may be one or more referenceframes corresponding to the current frame. For example, if the currentframe is a P frame, there may be one corresponding reference frame. Forexample, if the current frame is a B frame, there may be twocorresponding reference frames. The reference frame corresponding to thecurrent frame may be obtained according to a reference relationship.There may be different reference relationships according to variousvideo codec standards.

Specifically, after performing intra-frame prediction on an input videoframe that can be used as a reference frame to obtain correspondingencoded data, the encoding end may perform entropy decoding, inversequantization, and inverse transformation on the encoded data to obtain aprediction residual corresponding to each intra-frame prediction block,and then add the prediction residual to corresponding reference blocksin the input video frame to obtain reconstructed video blocks, so as toobtain a reconstructed frame, that is, the reference frame, for example,an I frame, of the input video frame.

Similarly, after performing inter-frame prediction on an input videoframe that can be used as a reference frame to obtain correspondingencoded data, the encoding end may perform entropy decoding, inversequantization, and inverse transformation on the encoded data to obtain aprediction residual corresponding to each inter-frame prediction block,and then add the prediction residual to corresponding reference blocksin the input video frame to obtain reconstructed video blocks, so as toobtain a reconstructed frame, that is, the reference frame, for example,a P frame, of the input video frame.

In an embodiment, the encoding end may buffer every reference framecorresponding to the input video frame sequence, and establish acorrespondence between a current frame and a reference frame. Theencoding end may directly acquire a corresponding reference frame duringencoding of a current frame from the buffer. The encoding end mayfurther acquire resolution information corresponding to the referenceframe.

In an embodiment, step S202 of acquiring a reference frame correspondingto a current frame includes: acquiring a first reference rule, the firstreference rule including a resolution value relationship between thecurrent frame and the reference frame; and acquiring the reference framecorresponding to the current frame according to the first referencerule.

Specifically, the first reference rule determines a resolution valuelimit relationship between a current frame and a reference frame. Theresolution value relationship includes at least one of the current frameand the reference frame having the same resolution or differentresolutions. If the first reference rule includes that the current frameand the reference frame have the same resolution, the first referencerule may further include a processing mode reference rule of theresolutions of the current frame and the reference frame. For example,the processing mode reference rule may include one or two of that areference frame using a full-resolution processing mode may bereferenced for a current frame using the full-resolution processing modeand a reference frame using the down-sampling processing mode may bereferenced for a current frame using the down-sampling processing mode.If the first reference rule includes that the current frame and thereference frame have different resolutions, the first reference rule mayfurther include one or two of that a resolution of the current frame isgreater than a resolution of the reference frame and the resolution ofthe current frame is less than the resolution of the reference frame.The first reference rule may include one or more of that a referenceframe with a down-sampled resolution may be referenced for a currentframe with an original resolution, a reference frame with an originalresolution may be referenced for a current frame with a down-sampledresolution, a reference frame with an original resolution may bereferenced for a current frame with an original resolution, and areference frame with a down-sampled resolution may be referenced for acurrent frame with a down-sampled resolution. The current frame with anoriginal resolution means that a resolution of the current frame is thesame as that of a corresponding input video frame, and the referenceframe with an original resolution means that a resolution of thereference frame is the same as that of an input video framecorresponding to the reference frame. The current frame with adown-sampled resolution means that the current frame is obtained byperforming down-sampling processing on a corresponding input videoframe. The reference frame with a down-sampled resolution means that thereference frame is obtained by performing down-sampling processing on acorresponding reference frame. After the first reference rule isobtained, the reference frame corresponding to the current frame isobtained according to the first reference rule. Therefore, the obtainedreference frame satisfies the first reference rule.

In an embodiment, during encoding of the current frame, the encoding endmay further add rule information corresponding to the first referencerule to the encoded data corresponding to the current frame.

Specifically, the rule information is used for describing the used firstreference rule. The encoding end may add a flag bitResolution_Referencer_Rules describing the processing mode to theencoded data. A specific value of the flag bit may be set as required.An addition position of the rule information in the encoded data may beone or more of corresponding group header information, sequence headerinformation, and frame header information. The addition position of therule information in the encoded data may be determined according to aneffect range of a first processing reference rule. For example, if thefirst reference rule is that a reference frame with a down-sampledresolution may be referenced for a current frame with an originalresolution, corresponding Resolution_Referencer_Rules may be 1. If thefirst reference rule is that a reference frame with a down-sampledresolution may be referenced for a current frame with a down-sampledresolution, corresponding Resolution_Referencer_Rules may be 2. If thesame first reference rule is used for a video frame sequence, anaddition position of the rule information in the encoded data may besequence header information. If different first reference rules may beused for GOPs in the video frame sequence, an addition position of therule information in the encoded data may be group header information.

S204: Determine a sub-pixel interpolation mode, the sub-pixelinterpolation mode comprising one of a direct sub-pixel interpolationmode and a sampled sub-pixel interpolation mode.

Sub-pixel interpolation is a process of performing interpolation byusing reference data of a whole pixel (also referred to as completepixel) in a reference frame to obtain reference data on a sub-pixellevel. For example, FIG. 6(1) and FIG. 6(2) are schematic diagrams ofperforming interpolation on a reference frame according to anembodiment. Referring to FIG. 6(1), pixels such as A1, A2, A3, B1, B2,and B3 are 2*2 whole pixels in the reference frame. Reference data ofsub-pixels are calculated according to reference data of these wholepixels. For example, an average may be obtained according to thereference data of the three whole pixels A1, A2, and A3 to calculatereference data of a sub-pixel a23, an average may be obtained accordingto the reference data of the three whole pixels A2, B2, and C2 tocalculate reference data of a sub-pixel a21, and reference data of asub-pixel a22 is then calculated according to the reference data of thesub-pixels a23 and a21, to implement interpolation with 1/2 pixelprecision on the reference frame. Referring to FIG. 6(2), pixels such asA1, A2, A3, B1, B2, and B3 are 4*4 whole pixels in the reference frame.Reference data of 15 sub-pixels is calculated according to referencedata of these whole pixels, to implement interpolation with 1/4 pixelprecision on the reference frame. For example, reference data of asub-pixel a8 is calculated according to the reference data of the wholepixels A2 and B2, and reference data of a sub-pixel a2 is calculatedaccording to the reference data of the whole pixels A2 and A3.Similarly, reference data of a total of 15 sub-pixels a1 to a15 iscalculated, to implement interpolation with 1/4 pixel precision on thewhole pixel A2. In the encoding process of the current frame, theencoding end needs to search the reference frame for a reference blockcorresponding to an encoded block in the current frame by using a motionsearch technology, a motion vector is calculated according to motioninformation of the encoded block relative to the reference block, andthe motion vector is encoded to inform the decoding end of the positionof the reference data corresponding to the reference block in thereference frame. Therefore, sub-pixel interpolation processing isperformed on the reference frame to obtain a target reference frame, andmotion estimation may be performed on the current frame according to thetarget reference frame with a higher resolution, so that the accuracy ofmotion estimation is improved and encoding quality is improved.

The sub-pixel interpolation mode is a mode of performing sub-pixelinterpolation processing on the acquired reference frame, includingdirectly performing sub-pixel interpolation processing on the referenceframe and performing sub-pixel interpolation processing after performingsampling processing on the reference frame.

Specifically, if the reference frame and the current frame have the sameresolution, the encoding end may directly perform sub-pixelinterpolation processing on the reference frame. If the reference frameand the current frame have different resolutions, the encoding end maydirectly perform sub-pixel interpolation processing on the referenceframe or may sample the reference frame to obtain a frame with aresolution the same as that of the current frame, and then performsub-pixel interpolation processing on the obtained frame with the sameresolution. The two sub-pixel interpolation modes are applicable. Thesampling of the current reference frame includes up-sampling processingand down-sampling processing. In an embodiment, if there are a pluralityof reference frames, each reference frame is sampled to obtain a framehaving a resolution the same as that of the current frame.

In this embodiment, the reference frame is sampled to obtain a framehaving a resolution the same as that of the current frame, so that animage matching degree between the current frame and the to-be-referencedframe can be somewhat improved, thereby improving the accuracy ofinter-frame prediction, reducing the prediction residual, and improvingthe quality of an encoded image.

In an embodiment, the encoding end and the decoding end may set inrespective codec rules sub-pixel interpolation modes used duringprocessing of the reference frame to obtain a target reference frame.The used sub-pixel interpolation modes are recommended to be consistent.Corresponding sub-pixel interpolation modes of processing the referenceframe are determined according to configurations during encoding anddecoding.

In an embodiment, if an adaptive-resolution encoding framework is usedto encode an input video frame, the encoding end may further addsub-pixel interpolation mode information corresponding to the sub-pixelinterpolation mode to encoded data corresponding to the current frame.The encoding end may add the sub-pixel interpolation mode information toheader information of the encoded data corresponding to the currentframe. Optionally, an addition position (that is, the headerinformation) of the sub-pixel interpolation mode information in theencoded data may be any one of sequence header information, group headerinformation, and frame header information of the encoded datacorresponding to the current frame. The addition position of thesub-pixel interpolation mode information in the encoded data may bedetermined according to an effect range corresponding to the sub-pixelinterpolation mode. For example, the encoding end may add the sub-pixelinterpolation mode information to the frame header information of theencoded data corresponding to the input video frame, indicating thatduring encoding of the input video frame, sub-pixel interpolationprocessing is performed on the corresponding reference frame by usingthe sub-pixel interpolation mode corresponding to the sub-pixelinterpolation mode information. For example, if the flag bitPixel_Sourse_Interpolation used for determining the sub-pixelinterpolation mode in the frame header information of the encoded datais 0, it indicates that sub-pixel interpolation processing is directlyperformed on the reference frame corresponding to the input video frame.If Pixel_Sourse_Interpolation is 1, it indicates that samplingprocessing is performed on the reference frame corresponding to theinput video frame before sub-pixel interpolation processing isperformed. The decoding end may perform sub-pixel interpolationprocessing on the reference frame by using the sub-pixel interpolationmode indicated by the flag bit in the encoded data to obtain a targetreference frame, so that the encoded data may be decoded according tothe target reference frame to obtain a reconstructed video frame.

For example, if a reference frame referenced for a current video frameto be encoded with a down-sampled resolution is a reconstructed framewith an original high resolution, a sequence header information syntaxelement (that is, the foregoing flag bit Pixel_Sourse_Interpolation usedfor determining a sub-pixel interpolation mode) may be defined forindicating whether a sub-pixel interpolation frame referenced for thecurrent video frame to be encoded is obtained by directly performingsub-pixel interpolation on a reconstructed frame with an original highresolution (that is, Pixel_Sourse_Interpolation is 0) or is obtained bydown-sampling the reconstructed frame with an original high resolutionto the down-sampled resolution (a resolution the same as that of thecurrent video frame to be encoded) and then performing sub-pixelinterpolation (that is, Pixel_Sourse_Interpolation is 1). The sequenceheader information syntax element may be an element on a sequence level,a video frame group level or a frame level.

For example, the sequence header information syntax element may be shownin the following Table 1.

TABLE 1 XXX header added information { Pixel_Sourse_Interpolation }

The XXX header added information shown in the foregoing Table 1 may beheader information of a video frame group or may be header informationon a single-frame level.

S206: Process the reference frame according to resolution information ofthe current frame by using the sub-pixel interpolation mode, to obtain acorresponding target reference frame.

The resolution information of the current frame may be a resolution ofthe current frame or may be down-sampling ratio informationcorresponding to the current frame obtained by performing down-samplingprocessing on the input video frame. For example, the resolutions ofinput video frames are all 2M*2N. Down-sampling processing is performedon the input video frame to obtain a current frame with a resolution ofM*N, so that the resolution information may be a resolution of M*N ofthe current frame or may be down-sampling ratio information, that is,1/2. For another example, the processing mode corresponding to thecurrent frame is a full-resolution processing mode, that is, the inputvideo frame is directly used as the current frame. In this case, theresolution information may be a resolution of 2M*2N of the current frameor may be down-sampling ratio information, that is, 1.

The target reference frame is a video frame obtained after sub-pixelinterpolation processing is performed on the reference frame accordingto a corresponding sub-pixel interpolation mode. Specifically, theencoding end may determine a sampling method corresponding to the usedsub-pixel interpolation mode according to a proportional relationshipbetween a resolution indicated by the resolution information of thecurrent frame and a resolution indicated by the resolution informationof the reference frame, the sampling method including an up-samplingmethod or a down-sampling method.

In an embodiment, the encoding end may determine a ratio for samplingthe reference frame according to the proportional relationship betweenthe resolution of the current frame and a resolution of the referenceframe. For example, the resolutions of input video frames are all 2M*2N.A current input video frame is processed by using the full-resolutionprocessing mode. That is, the current input video frame is directly usedas the current frame to be encoded. The resolution of the current frameis 2M*2N. An input video frame that can be used as a reference frame isprocessed by using the down-sampling processing mode, to obtain that aresolution of the down-sampled reference frame to be encoded is M*2N.The resolution of a reconstructed corresponding reference frame is alsoM*2N. In this case, it is determined that up-sampling processing isperformed on the reference frame by using a sampling ratio of the doublewidth and the same height, to obtain a frame with a resolution the sameas that of the current frame. If the encoding end performs processing onthe current input video frame by using the down-sampling processingmode, the resolution of a down-sampled video frame to be encoded is M*N.An input video frame that can be used as a reference frame is processedby using the full-resolution processing mode. In this case, theresolution of the reconstructed reference frame is 2M*2N. It isdetermined that down-sampling processing is performed on the referenceframe by using a sampling ratio of a width of 1/2 and a height of 1/2,to obtain a frame with a resolution the same as that of the currentframe.

In an embodiment, because input video frames generally have the sameresolution, the encoding end may determine a proportion for sampling thereference frame according to a down-sampling ratio corresponding to acurrent frame obtained by down-sampling an input video frame and adown-sampling ratio corresponding to a reference frame to be encodedobtained by down-sampling an input video frame that can be used as areference frame. For example, down-sampling processing is performed onthe input video frame by using a sampling ratio of 1/2 to obtain acurrent frame, and down-sampling processing is performed on an inputvideo frame that can be used as a reference frame by using a samplingratio of 1/4 to obtain a reference frame to be encoded. In this way, adown-sampling ratio corresponding to the reference frame reconstructedaccording to the encoded data of the reference frame to be encoded isalso 1/4. In this case, according to a multiple relationship between thetwo down-sampling ratios, it may be determined that up-samplingprocessing is performed on the reference frame by using a sampling ratioof 2 to obtain a frame with a resolution the same as that of the currentframe.

In an embodiment, a sampling method for sampling the reference frame bythe encoding end matches a sampling algorithm of down-sampling the inputvideo frame to obtain the current frame. That is, if the reference frameneeds to be down-sampled, a down-sampling algorithm is the same as thedown-sampling algorithm of down-sampling the input video frame to obtainthe current frame. If the reference frame needs to be up-sampled, anup-sampling algorithm is an inverse sampling algorithm matching thedown-sampling algorithm of down-sampling the input video frame to obtainthe current video frame to be encoded.

In this embodiment, the sampling algorithm for sampling the referenceframe matches the sampling algorithm by which the current frame isdown-sampled to obtain the current encoded video frame, to furtherincrease an image matching degree between the reference frame and thecurrent encoded video frame, thereby further improving the accuracy ofinter-frame prediction, reducing the prediction residual, and improvingthe quality of an encoded image.

S208: Encode the current frame according to the target reference frame,to obtain encoded data corresponding to the current frame.

Specifically, the encoding may include at least one of prediction,transformation, quantization, and entropy encoding. If the current frameis a P frame or a B frame, the encoding end may acquire the referenceframe corresponding to the current frame, perform prediction accordingto the reference frame to obtain a prediction residual, and performtransformation, quantization, entropy encoding, and the like on theprediction residual to obtain encoded data corresponding to the inputvideo frame. In the process of obtaining the encoded data, at least oneof position information and a motion vector corresponding to eachencoding block in the reference frame and the current frame is processedaccording to the resolution of the current frame. For example, duringthe calculation of the prediction residual, the encoding end may processthe reference frame according to the resolution information of thecurrent frame, to obtain the target reference frame, acquire a referenceblock corresponding to each encoded block in the current frame from thetarget reference frame, perform prediction according to the referenceblock, to obtain a predicted value corresponding to the encoded block,and then obtain a prediction residual according to a difference betweenan actual value and the predicted value of the encoded block. As theencoding end calculates a target motion vector, if the resolution of thereference frame is different from the resolution of the current frame,the encoding end may transform the position information of the encodedblock or the position information of the decoded block according to theresolutions of the reference frame and the current frame, and obtain thetarget motion vector according to the transformed position information,to reduce the value of the target motion vector, thereby reducing a dataamount of the encoded data. Alternatively, if resolution informationcorresponding to the target motion vector is different from theresolution information of the current frame, during the calculation of afirst motion vector corresponding to an encoded block in the currentframe, the first motion vector is transformed according to theresolution information of the current frame and the resolutioninformation corresponding to the target motion vector, to obtain thetarget motion vector. For example, assuming that the resolution of thecurrent frame is 400*800 pixels, and the resolution of the referenceframe is 800*1600 pixels. 1/2 down-sampling may be performed on thereference frame according to the resolution of the current frame, toobtain that the resolution of the target reference frame is 400*800pixels, and video encoding is performed according to the targetreference frame. If resolution information corresponding to the currentframe is different from the resolution information corresponding to thereference frame, the position information of the encoded blockcorresponding to the current frame is transformed, to obtain atransformed position.

In an embodiment, the encoding end may further add correspondingsampling mode information for processing the reference frame to encodeddata corresponding to the reference frame. The encoding end may furtheracquire a corresponding encoding mode during encoding of the currentframe, and add encoding mode information corresponding to the encodingmode to the encoded data corresponding to the input video frame.

Specifically, the encoding mode is a processing mode related to encodingby the encoding end. For example, one or more up-sampling modes used fora video frame obtained after the reference frame is decoded andreconstructed during encoding, a rule corresponding to a reference rule,and sub-pixel interpolation of the reference frame. The encoding modeinformation corresponding to the encoding mode is added to the encodeddata corresponding to the input video frame, so that the decoding endmay decode a current frame according to the encoding mode information.

In an embodiment, the encoding end may not add the encoding modeinformation corresponding to the encoding mode to the encoded data.Instead, an encoding mode is preset at the encoding end, and a decodingmode corresponding to the encoding mode is set at the decoding end.Alternatively, the encoding end and the decoding end may calculate thecorresponding encoding mode and decoding mode according to the samealgorithm or corresponding algorithms. For example, it may be preset ina codec standard that the up-sampling method of the reference frame bythe encoding end is the same as the up-sampling method of the referenceframe by the decoding end.

By using the foregoing video encoding method, after a reference framecorresponding to a current frame is acquired, a sub-pixel interpolationmode of the reference frame may be determined, and the reference frameis processed according to resolution information of the reference frameby using the sub-pixel interpolation mode, to adjust a resolution of thereference frame, to obtain a target reference frame. Even if theresolution of the reference frame is different from that of the currentframe, the reference frame may be used as a reference frame for thecurrent frame. The current frame is encoded according to the obtainedtarget reference frame, thereby improving the utilization efficiency ofreference frames, so that the accuracy of inter-frame prediction can beimproved, a prediction residual can be reduced, and the quality of anencoded image can be improved.

As shown in FIG. 7, in an embodiment, step S206 of processing thereference frame according to resolution information of the current frameby using the sub-pixel interpolation mode, to obtain a correspondingtarget reference frame specifically includes the following steps.

S702: Acquire motion estimation pixel precision corresponding to thecurrent frame.

The motion estimation pixel precision is a unit length of a motionvector corresponding to an encoded block in the current frame. If theencoding end encodes an encoded block in the current frame, the unitlength of the motion vector corresponding to the encoded block may besubdivided according to the acquired motion estimation pixel precision.In this way, the obtained motion vector is more precise and accurate.The encoding end needs to perform sub-pixel interpolation processing onthe reference frame according to the acquired motion estimation pixelprecision to obtain a target reference frame, then calculate a motionvector corresponding to each encoded block in the current frameaccording to the target reference frame, and perform encoding based onthe motion vector to obtain the encoded data corresponding to thecurrent frame.

S704: Process the reference frame according to the resolutioninformation of the current frame and the motion estimation pixelprecision by using the sub-pixel interpolation mode, to obtain thecorresponding target reference frame.

Specifically, the encoding end may acquire the resolution information ofthe reference frame, and determine, according to the sub-pixelinterpolation mode used for the current frame, the resolutioninformation of the current frame, the resolution information of thereference frame, and the motion estimation pixel precision correspondingto the current frame, which sampling processing is to be used for thereference frame, a sampling ratio corresponding to the samplingprocessing, and pixel interpolation precision.

In an embodiment, the motion estimation pixel precision is generally 1/2pixel precision, 1/4 pixel precision or 1/8 pixel precision. Motionestimation with higher precision may not significantly improve theencoding quality, but causes significant increase in calculationcomplexity.

In an embodiment, the encoding end may configure corresponding motionestimation pixel precision for the current frame according to imagefeature information of the current frame. The image feature informationis, for example, the size, texture information, motion speed, and thelike of the current frame, and various types of image featureinformation may be combined to determine the motion estimation pixelprecision corresponding to the current frame. If image data carried inthe current frame is more complex and image information is richer, thecorresponding motion estimation pixel precision is higher. For example,during inter-frame prediction of a P frame, relatively high motionestimation pixel precision may be used to calculate motion vectorscorresponding to encoded blocks in the P frame. During inter-frameprediction of a B frame, relatively low motion estimation pixelprecision may be used to calculate motion vectors corresponding toencoded blocks in the B frame.

As shown in FIG. 8, in an embodiment, step S704 of processing thereference frame according to the resolution information of the currentframe to be encoded and the motion estimation pixel precision by usingthe sub-pixel interpolation mode, to obtain the corresponding targetreference frame includes the following steps.

S802: If the sub-pixel interpolation mode is a sampled sub-pixelinterpolation mode and a resolution indicated by the resolutioninformation of the current frame is less than a resolution of thereference frame, perform down-sampling processing on the reference frameaccording to the resolution information of the current frame to obtainan intermediate reference frame.

Specifically, if the sub-pixel interpolation mode corresponding to thecurrent frame is a sampled sub-pixel interpolation mode, it indicatesthat sampling processing needs to be performed first on the referenceframe to obtain an intermediate reference frame with a resolution thesame as that of the current frame, and sub-pixel interpolationprocessing is then performed on the intermediate reference frame toobtain the corresponding target reference frame.

S804: Perform sub-pixel interpolation processing on the intermediatereference frame according to the motion estimation pixel precision, toobtain the corresponding target reference frame.

As discussed above, if a resolution indicated by the resolutioninformation of the current frame is less than a resolution of thereference frame, the encoding end needs to determine a sampling ratio ofperforming down-sampling on the reference frame according to theproportional relationship between the two resolutions, and performdown-sampling according to the sampling ratio to obtain an intermediatereference frame with a resolution the same as that of the current frame;and then perform sub-pixel interpolation processing on the intermediatereference frame based on the motion estimation pixel precision, toobtain the target reference frame. In addition, in this case, the pixelinterpolation precision is the same as the motion estimation pixelprecision.

For example, the encoding end performs down-sampling processing on aninput video frame with a resolution of 2M*2N by using the down-samplingprocessing mode to obtain a current frame with a resolution of M*N. Theresolution of the reference frame is 2M*2N (the full-resolutionprocessing mode). Down-sampling processing is performed on the referenceframe according to a sampling ratio of 1/2 to obtain an intermediatereference frame with a resolution of M*N. If the motion estimation pixelprecision corresponding to the acquired video frame to be encoded is1/2, sub-pixel interpolation processing is then performed on theintermediate reference frame according to pixel interpolation precisionthe same as the motion estimation pixel precision, that is, sub-pixelinterpolation precision of 1/2, to obtain the target reference frame. Ifthe motion estimation pixel precision corresponding to the acquiredvideo frame to be encoded is 1/4, sub-pixel interpolation processing isperformed on the intermediate reference frame according to the sub-pixelinterpolation precision of 1/4, to obtain a target reference frame witha higher resolution.

Certainly, the reference frame may also be obtained using thedown-sampling processing mode. For example, the encoding end performsdown-sampling processing on the input video frame with a resolution of2M*2N according to the down-sampling processing mode to obtain a currentframe with a resolution of 1/2M*1/2N. The reference frame is obtainedthrough reconstruction after down-sampling processing is performed on aninput video frame with a resolution of 2M*2N to obtain encoded datacorresponding to a reference frame to be encoded with a resolution ofM*N. In this case, the resolution of the reference frame is also M*N.Therefore, the resolution of the current frame is less than a resolutionof the reference frame. Down-sampling processing may be performed on thereference frame according to a sampling ratio of 1/2 to obtain anintermediate reference frame with a resolution the same as that of thecurrent frame. Sub-pixel interpolation processing is then performedbased on the motion estimation pixel precision to obtain the targetreference frame.

As shown in FIG. 9, in an embodiment, step S704 of processing thereference frame according to the resolution information of the currentframe to be encoded and the motion estimation pixel precision by usingthe sub-pixel interpolation mode, to obtain the corresponding targetreference frame includes the following steps.

S902: If the sub-pixel interpolation mode is a direct sub-pixelinterpolation mode and a resolution indicated by the resolutioninformation of the current frame is less than a resolution of thereference frame, perform calculation according to the resolutioninformation of the current frame and the motion estimation pixelprecision to obtain pixel interpolation precision.

S904: Directly perform sub-pixel interpolation processing on thereference frame according to the pixel interpolation precision, toobtain the corresponding target reference frame.

Specifically, if the sub-pixel interpolation mode corresponding to thecurrent frame is a direct sub-pixel interpolation mode, it indicatesthat sub-pixel interpolation processing may be directly performed on thereference frame to obtain the target reference frame. It may beunderstood that because the resolution of the reference frame is greaterthan the resolution of the current frame, data of some sub-pixels in thereference frame may be directly reused, and may be used as datacorresponding to sub-pixels corresponding to the motion estimation pixelprecision.

For example, the resolution of the current frame is M*N, and theresolution of the reference frame is 2M*2N. If the motion estimationpixel precision is 1/2, the reference frame may be directly used as thetarget reference frame. If the motion estimation pixel precision is 1/4,it is calculated that the pixel interpolation precision is 1/2, andsub-pixel interpolation processing may be performed on the referenceframe by using pixel interpolation precision of 1/2 to obtain the targetreference frame.

As shown in FIG. 10, in an embodiment, step S704 of processing thereference frame according to the resolution information of the currentframe to be encoded and the motion estimation pixel precision by usingthe sub-pixel interpolation mode, to obtain the corresponding targetreference frame includes the following steps.

S1002: If the sub-pixel interpolation mode is a sampled sub-pixelinterpolation mode and a resolution indicated by the resolutioninformation of the current frame is greater than a resolution of thereference frame, perform up-sampling processing on the reference frameaccording to the resolution information of the current frame to obtainan intermediate reference frame.

S1004: Perform sub-pixel interpolation processing on the intermediatereference frame according to the motion estimation pixel precision, toobtain the corresponding target reference frame.

As discussed above, if the resolution of the current frame is greaterthan a resolution of the reference frame, the encoding end needs toperform up-sampling processing on the reference frame to obtain anintermediate reference frame with a resolution the same as that of thecurrent frame; and then perform sub-pixel interpolation processing onthe intermediate reference frame based on the motion estimation pixelprecision corresponding to the current frame, to obtain the targetreference frame.

For example, the resolution of the current frame is 2M*2N, and theresolution of the reference frame is 1/2M*1/2N. Up-sampling processingneeds to be performed on the reference frame according to a samplingratio of 1/4 to obtain an intermediate reference frame with a resolutionthe same as that of the current frame. If the motion estimation pixelprecision is 1/2, sub-pixel interpolation processing continues to beperformed on the obtained intermediate reference frame according to thepixel interpolation precision of 1/2, to obtain the target referenceframe. If the motion estimation pixel precision is 1/4, sub-pixelinterpolation processing continues to be performed on the obtainedintermediate reference frame according to the pixel interpolationprecision of 1/4, to obtain the target reference frame.

In an embodiment, the processing the reference frame according to theresolution information of the current frame and the motion estimationpixel precision by using the sub-pixel interpolation mode, to obtain thecorresponding target reference frame includes: if the sub-pixelinterpolation mode is a direct sub-pixel interpolation mode and aresolution indicated by the resolution information of the current frameis the same as a resolution of the reference frame, directly performingsub-pixel interpolation processing on the reference frame according tothe motion estimation pixel precision, to obtain the correspondingtarget reference frame.

Specifically, the input video frame is processed by using thefull-resolution processing mode to obtain the current frame, and if theresolution of the reference frame is also the original resolution, theresolution of the current frame is the same as the resolution of thereference frame. Alternatively, the input video frame is processed byusing the down-sampling mode to obtain the current frame, and if thereference frame is also reconstructed through encoded data obtained byperforming encoding using the down-sampling mode with the same samplingratio, the resolution of the current frame is the same as the resolutionof the reference frame. In this case, the encoding end may directlyperform sub-pixel interpolation processing on the reference frame basedon the motion estimation pixel precision to obtain the target referenceframe, and the pixel interpolation precision corresponding to thesub-pixel interpolation processing is the same as the motion estimationpixel precision.

In the foregoing embodiment, sub-pixel interpolation processing isperformed on the reference frame, so that the resolution of thereference frame is higher. In this way, the calculated video frame to beencoded is more precise than the motion vector of the reference frame,thereby further reducing a prediction residual, so that encoding qualitycan be improved.

In an embodiment, as shown in FIG. 11, step S208 of encoding the currentframe according to the target reference frame, to obtain encoded datacorresponding to the current frame includes the following steps.

S1102: Determine a first vector transformation parameter according tothe resolution information of the current frame to be encoded and firstresolution information, the first resolution information includingtarget motion vector unit resolution information corresponding to aninput video frame.

Specifically, the first vector transformation parameter is used fortransforming a motion vector or position information of the motionvector, to obtain a transformed motion vector or position. Theresolution information is information related to a resolution, and maybe, for example, a resolution or a down-sampling ratio. The first vectortransformation parameter may be a ratio of the resolution information ofthe current frame to the first resolution information and may beobtained by dividing the resolution information of the current frame bythe first resolution information, or may be obtained by dividing thefirst resolution information by the resolution information of thecurrent frame, or may be obtained by multiplying the proportion by acorresponding coefficient or adding a preset offset to the proportionafter the proportion is obtained. For example, assuming that thedown-sampling ratio of the reference frame is 1/3, the down-samplingratio of the current frame is 1/6. The first vector transformationparameter may be 2 obtained by dividing 1/3 by 1/6.

S1104: Obtain a target motion vector corresponding to each encoded blockin the current frame according to the first vector transformationparameter.

Specifically, after obtaining the first vector transformation parameter,the encoding end transforms the obtained motion vector or the positioninformation corresponding to the motion vector according to the firstvector transformation parameter, to obtain the target motion vector.

In an embodiment, step S1102 of determining a first vectortransformation parameter according to the resolution information of thecurrent frame and first resolution information includes: acquiring thetarget motion vector unit resolution information; and determining thefirst vector transformation parameter according to the resolutioninformation of the current frame and the target motion vector unitresolution information.

Specifically, the target motion vector unit resolution information isinformation related to a resolution corresponding to the unit of thetarget motion vector, and may be, for example, a resolution or adown-sampling ratio. The resolution corresponding to the unit of thetarget motion vector means that the unit of the target motion vector iscalculated by using the vector unit at the resolution as a standard. Theresolutions of some video frames to be encoded corresponding to an inputvideo frame sequence may be the same as the original resolution of theinput video frame, and the resolutions of some other video frames to beencoded are less than the original resolution of the input video frame.That is, the video frames to be encoded may have one or moreresolutions. Therefore, the resolution corresponding to the unit of thetarget motion vector needs to be determined. The resolutioncorresponding to the unit of the target motion vector may be set beforeencoding or obtained according to a parameter of an encoding process,and may be specifically set as required.

In an embodiment, the resolution corresponding to the unit of the targetmotion vector may be a resolution corresponding to the input videoframe, that is, the original resolution. Alternatively, the resolutioncorresponding to the unit of the target motion vector may be aresolution corresponding to the current frame. The first vectortransformation parameter may be a ratio of resolution informationcorresponding to the unit of the target motion vector to the resolutioninformation of the current frame. For example, assuming that theresolution corresponding to the unit of the target motion vector is theoriginal resolution, the sampling ratio corresponding to the unit of thetarget motion vector is 1, and the sampling ratio of the resolution ofthe current frame is 1/2, the first vector transformation parameter maybe 2 obtained by dividing 1 by 1/2. Alternatively, assuming that theresolution corresponding to the unit of the target motion vector is theoriginal resolution and is 900*900 pixels, and the sampling ratio of theresolution of the current frame is 450*600 pixels, there may be twofirst vector transformation parameters, namely, a first vectortransformation parameter in a horizontal direction and a first vectortransformation parameter in a vertical direction. The first vectortransformation parameter in the horizontal direction is 900/450=2, andthe first vector transformation parameter in the vertical direction is900/600=1.5.

In an embodiment, the encoding end may obtain the target motion vectorunit resolution information according to a computing capability of adevice that performs encoding. For example, the operation time is longif the device that performs encoding can only perform operation on aninteger or if the computation on a decimal value consume a lot of time.In this case, the resolution corresponding to the unit of the targetmotion vector may be a resolution corresponding to the input videoframe. If the device that performs encoding performs operation on adecimal value fast, the resolution corresponding to the unit of thetarget motion vector may be a resolution corresponding to the currentframe.

In an embodiment, if the first vector transformation parameter isdetermined according to the resolution information of the current frameand the target motion vector unit resolution information, step S1104 ofobtaining a target motion vector corresponding to each encoded block inthe current frame according to the first vector transformation parameterincludes: obtaining a first motion vector according to displacements ofa current encoded block and a corresponding target reference block; andobtaining a target motion vector corresponding to the current encodedblock according to the first vector transformation parameter and thefirst motion vector.

Specifically, the first motion vector is obtained according to thedisplacements of the current encoded block and the corresponding targetreference block, and the target reference block may be acquired from thetarget reference frame obtained after the reference frame is processed.After the first motion vector is obtained, the first vectortransformation parameter may be multiplied by the first motion vector,and the obtained product is used as the target motion vector. Assumingthat the resolution corresponding to the unit of the target motionvector is the original resolution, because the unit of the target motionvector is the original resolution and the first motion vector isobtained through calculation at the resolution of the current frame, thefirst motion vector needs to be transformed. If the first vectortransformation parameter is equal to 2, the obtained first motion vectoris (2, 2), then the target motion vector is (4, 4). After the targetmotion vector is obtained, encoding may be performed according to thetarget motion vector. For example, the target motion vector and theprediction residual corresponding to the current encoded block may beencoded to obtain the encoded data.

In an embodiment, if the resolution information of the current frame isconsistent with the target motion vector unit resolution information,the first vector transformation parameter is 1, and the first motionvector is the same as the target motion vector. In this case, step S1102may be skipped, and the first motion vector is used as the target motionvector. If the resolution information of the current frame is notconsistent with the target motion vector unit resolution information,step S1102 is performed.

In an embodiment, if the resolution information of the current frame isdifferent from that of the target reference frame, the step of obtainingthe first motion vector includes: determining a third vectortransformation parameter according to the resolution information of thecurrent frame and resolution information of the target reference frame;and obtaining the first motion vector corresponding to each encodedblock in the current frame according to the third vector transformationparameter.

In an embodiment, the obtaining the first motion vector corresponding toeach encoded block in the current frame according to the third vectortransformation parameter includes: acquiring first position informationcorresponding to the current encoded block, and acquiring secondposition information corresponding to the target reference blockcorresponding to the current encoded block; and calculating the firstmotion vector corresponding to the current encoded block according tothe third vector transformation parameter, the first positioninformation, and the second position information.

Specifically, the current encoded block is an encoded block thatcurrently requires predicted encoding in the input video frame. Thetarget reference block is an image block used for performing predictedencoding on the current encoded block in the target reference frame. Thefirst position information corresponding to the current encoded blockmay be represented by coordinates of a pixel. The first positioninformation corresponding to the current encoded block may includecoordinates corresponding to all pixels of the current encoded block.The first position information corresponding to the current encodedblock may alternatively include coordinates of one or more pixels of thecurrent encoded block. The first position information corresponding tothe current encoded block may include coordinates corresponding to allpixels of the current encoded block. The first position informationcorresponding to the current encoded block may alternatively includecoordinates of one or more pixels of the current encoded block. Thesecond position information corresponding to the target reference blockmay include coordinates corresponding to all pixels of the targetreference block. The second position information corresponding to thetarget reference block may alternatively include coordinates of one ormore pixels of the target reference block. For example, the coordinatesof the first pixel of a current image block may be used as a coordinatevalue of the current encoded block, and the coordinates of the firstpixel of the target reference block are used as a coordinate value ofthe target reference block.

The encoding end may transform the first position information by usingthe third vector transformation parameter to obtain corresponding firsttransformed position information, and a first motion vector is obtainedaccording to a difference between the first transformed positioninformation and the second position information. Alternatively, theencoding end may transform the second position information by using thethird vector transformation parameter to obtain corresponding secondtransformed position information, and a first motion vector is obtainedaccording to a difference between the first position information and thetransformed second position information.

In an embodiment, the third vector transformation parameter is aproportion obtained by dividing high resolution information by lowresolution information in the resolution information of the currentframe and the resolution information of the target reference frame. Aresolution corresponding to the high resolution information is greaterthan a resolution corresponding to the low resolution information. Thethird vector transformation parameter is used for transforming positioninformation of the frame with the low resolution information in thecurrent frame and the target reference frame. For example, theresolution of the current frame is 1200*1200 pixels, and the resolutionof the target reference frame is 600*600 pixels, so that the highresolution is 1200*1200 pixels, and the low resolution is 600*600pixels. The first vector transformation parameter may be 2. Assumingthat the first position information is (6, 8) and the second positioninformation is (3, 3). The first motion vector is (6, 8)−(3*2, 3*2)=(0,2). In this embodiment of the present application, the positioninformation corresponding to the frame with the low resolutioninformation is transformed, so that the value of the first motion vectorcan be reduced, thereby reducing a data amount of encoded data.

In this embodiment of the present application, the resolutioncorresponding to the unit of the first motion vector is the resolutioncorresponding to the input video frame, that is, the originalresolution. For an input video frame sequence with the same resolution,units of the target motion vectors corresponding to the input videoframes are consistent, so that the continuity of the target motionvector can be kept. If the resolution corresponding to the unit of thetarget motion vector is the resolution corresponding to the currentframe, because the resolution information of the current frame isconsistent with the target motion vector unit resolution information, itis not necessary to transform the first motion vector, so that acalculation time can be reduced.

In an embodiment, as shown in FIG. 12, step S208 of encoding the currentframe according to the target reference frame, to obtain encoded datacorresponding to the current frame includes the following steps.

S1202: Acquire an initial predicted motion vector corresponding to acurrent encoded block.

Specifically, to reduce a quantity of bits for the encoded data, theencoding end may predict the motion vector of the current encoded blockto obtain a predicted value, calculate a difference between the targetmotion vector and the predicted value, to obtain a motion vectordifference, and encode the motion vector difference. The initialpredicted motion vector is used for predicting the motion vector of thecurrent encoded block. There may be one or more initial predicted motionvectors. This may be specifically set as required. An acquisition ruleof the initial predicted motion vector may be set as required. Becausethe current encoded block is usually spatially correlated to an adjacentencoded block thereof. Therefore, a target motion vector valuecorresponding to one or more adjacent encoded blocks corresponding tothe current encoded block may be used as the initial predicted motionvector. For example, a first motion vector value corresponding toadjacent encoded blocks on the upper right corner and the upper leftcorner in the current encoded block may be used as the initial predictedmotion vector.

S1204: Obtain a second vector transformation coefficient according tocurrent motion vector unit resolution information and target motionvector unit resolution information corresponding to the initialpredicted motion vector.

Specifically, the current motion vector unit resolution information isinformation related to the resolution corresponding to the unit of thetarget motion vector, and may be, for example, a resolution or adown-sampling ratio. The resolution corresponding to the unit of theinitial predicted motion vector means that the unit of the initialpredicted motion vector is calculated by using the vector unit at theresolution as a standard. If the current motion vector unit resolutioninformation corresponding to the initial predicted motion vector isdifferent from the target motion vector unit resolution information, theencoding end needs to obtain a second vector transformation coefficientaccording to the current motion vector unit resolution information andthe target motion vector unit resolution information corresponding tothe initial predicted motion vector. The first vector transformationparameter may be a proportion of resolution information corresponding tothe unit of the target motion vector to the current motion vector unitresolution information. For example, assuming that the resolutioncorresponding to the unit of the target motion vector is 200*200 pixels,and the current motion vector unit resolution information is 100*100pixels, the first vector transformation parameter may be 2.

S1206: Obtain a target predicted motion vector corresponding to thecurrent encoded block according to the initial predicted motion vectorand the second vector transformation coefficient.

Specifically, after the second vector transformation coefficient isobtained, operation is performed according to the initial predictedmotion vector and the second vector transformation coefficient, toobtain the target predicted motion vector. For example, if there is oneinitial predicted motion vector, a product of the initial predictedmotion vector and the second vector transformation coefficient may beused as the target predicted motion vector. If there are a plurality ofinitial predicted motion vectors, the encoding end may calculate theinitial predicted motion vector to obtain a calculation result, andobtain the target motion vector according to the calculation result andthe second vector transformation coefficient. The calculation result maybe one or more of a minimum value, an average value, and a median valuein the initial predicted motion vectors. It may be understood that analgorithm for obtaining the target predicted motion vector according tothe initial predicted motion vector and the second vector transformationcoefficient may be customized, and a matching customized algorithm maybe used at the decoding end to calculate the same target predictedmotion vector.

S1208: Obtain a motion vector difference according to the target motionvector and the target predicted motion vector.

Specifically, a difference between the target motion vector and thetarget predicted motion vector may be used as the motion vectordifference, to perform encoding according to the motion vectordifference to obtain the encoded data, thereby reducing a data amount ofthe encoded data.

In an embodiment, as shown in FIG. 13, a video decoding method isprovided. An example in which the method is applied to the terminal 110or server 120 in the application environment shown in FIG. 1 is used fordescription, and the method includes the following steps.

S1302: Acquire encoded data corresponding to a current frame to bedecoded from a video input.

The current frame is a video frame that needs to be decoded, and theencoded data is data for decoding. The decoding end may receive, througha network, the encoded data transmitted by the encoding end. The encodeddata may be obtained by encoding the input video frame by using afull-resolution processing mode by the encoding end or may be obtainedafter the encoding end performs down-sampling on the input video frameby using a corresponding down-sampling processing mode and then performsencoding.

In an embodiment, the decoding end may acquire processing modeinformation corresponding to the current frame from header informationof the encoded data. After obtaining a reconstructed video framecorresponding to the current frame, the decoding end may process thereconstructed video frame by using a mode matching the processing modeinformation, to obtain a decoded video frame. Specifically, the headerinformation may be frame header information of the encoded data,indicating a processing mode used in encoding of the input video framecorresponding to the current encoded data. For example, if a flag bitFrame_Resolution_Flag used for determining a processing mode in frameheader information of the encoded data is 0, it indicates that the inputvideo frame is encoded by using the full-resolution processing mode, andthe reconstructed video frame obtained by decoding the encoded data bythe decoding end is a decoded video frame corresponding to the currentframe. If Frame_Resolution_Flag is 1, it indicates that the input videoframe is encoded by using the down-sampling processing mode. Thedecoding end may further process the obtained reconstructed video frameby using the processing mode matching the down-sampling processing mode,to obtain the decoded video frame. The further processing is, forexample, up-sampling processing.

In an embodiment, the decoding end may determine a decoding frameworkcorresponding to the current frame from the header information of theencoded data. Specifically, the decoding end may acquire an encodingframework used for each input video frame in the input video framesequence corresponding to the current encoded data during encoding, soas to determine a decoding framework of the current frame matching theencoding framework. For example, if a flag bit Sequence_Mix_Flag usedfor determining the used encoding framework in the sequence headerinformation of the encoded data is 0, it indicates that all the inputvideo frames in the input video frame sequence are encoded by using theconstant-resolution encoding framework, and the decoding end may decodethe encoded data by using a constant-resolution decoding framework toobtain a reconstructed video frame corresponding to the current frame.If Sequence_Mix_Flag is 1, it indicates that all the input video framesin the input video frame sequence are encoded by using anadaptive-resolution encoding framework, so that the decoding end maydecode the encoded data by using an adaptive-resolution decodingframework to obtain a reconstructed video frame sequence.

FIG. 14 is a diagram showing a decoding framework corresponding to avideo decoding method according to an embodiment. By using the videodecoding method provided in this embodiment of this application, anencoded data acquisition unit 1400 may acquire encoded datacorresponding to each frame to be decoded in a frame sequence. Anentropy decoding unit 1402 performs entropy decoding to obtain entropydecoded data. A second inverse quantization unit 1404 performs inversequantization on the entropy decoded data to obtain inversely quantizeddata. A second inverse transformation unit 1406 performs inversetransformation on the inversely quantized data to obtain inverselytransformed data. The inversely transformed data may be consistent withthe data obtained after the first inverse transformation unit 414 inFIG. 4 performs inverse transformation. A second reference informationadaptation unit 1412 is configured to: acquire a reference framereconstructed by a second reconstruction unit 1410, perform adaptiveprocessing on at least one of reference information such as thereference frame, position information corresponding to each video blockto be decoded in a video frame to be decoded, position informationcorresponding to each reference block in the reference frame, and amotion vector according to resolution information of the current frame,and perform prediction according to information obtained after adaptiveprocessing. A second prediction unit 1414 acquires a reference blockcorresponding to the video block to be decoded according to referenceinformation obtained after adaptive processing, and obtains a predictedvalue consistent with the predicted value in FIG. 4 according to animage value of the reference block. The second reconstruction unit 1410performs reconstruction according to the predicted value and theinversely transformed data (that is, a prediction residual), to obtain areconstructed video frame. A second processing unit 1416 performsprocessing on the reconstructed video frame according to resolutioninformation corresponding to the current frame, to obtain acorresponding decoded video frame. A playback/storage unit 1418 may playor store the decoded video frame or play and store the decoded videoframe.

In an embodiment, if the decoding end decodes the encoded data by usingthe adaptive-resolution decoding framework, the decoding end may furtherdetermine a processing mode corresponding to the current encoded dataaccording to a decision algorithm. The decision algorithm matches adecision algorithm used by the encoding end to encode the input videoframe.

In an embodiment, if the current encoded data determined by the decodingend from the header information of the encoded data is obtained throughencoding using the down-sampling processing mode, the decoding end mayfurther acquire the used down-sampling ratio information ordown-sampling method information from the header information, andperform up-sampling processing on the obtained reconstructed video frameusing an up-sampling ratio matching the down-sampling ratio informationor an up-sampling method matching the down-sampling method information,to obtain a decoded video frame. For example, the sampling ratiocorresponding to the down-sampling ratio information is 1/2. Thedecoding end needs to perform up-sampling processing on thereconstructed video frame according to the sampling ratio of 1/2 and theup-sampling method matching the down-sampling method information, toobtain a decoded video frame. The decoding end may acquire thedown-sampling ratio information or the down-sampling method informationcorresponding to the current encoded data from any one of sequenceheader information, group header information, and frame headerinformation.

S1304: Acquire a reference frame corresponding to the current frame tobe decoded.

The reference frame is a video frame that needs to be referenced duringdecoding of the current frame. The reference frame is a video frameobtained by reconstructing encoded data corresponding to a video framethat can be used as a reference frame. According to differentinter-frame prediction types, the reference frame corresponding to acurrent video frame to be encoded may be a forward reference frame or abidirectional reference frame, and there may be one or more referenceframes corresponding to the current frame. The reference frame in thevideo decoding method corresponds to the reference frame in the videoencoding method.

Specifically, after acquiring the encoded data corresponding to thereference frame, the decoding end may perform entropy decoding, inversequantization, and inverse transformation on the encoded data to obtain aprediction residual corresponding to each intra-frame prediction block,and then add the prediction residual to corresponding reference blocksto obtain reconstructed video blocks, so as to obtain a reconstructedframe, that is, the reference frame, for example, an I frame, of theinput video frame.

In an embodiment, the decoding end may buffer reference framescorresponding to the current frame, and establish a correspondencebetween a current frame and a reference frame. A corresponding referenceframe may be directly acquired during decoding of the current frame.Resolution information corresponding to the reference frame may furtherbe acquired. For example, for one GOP, one same previous reference frameusually needs to be referenced for a plurality of subsequent videoframes to be decoded.

In an embodiment, step S1304 of acquiring a reference framecorresponding to the current frame specifically includes: acquiring asecond reference rule, the second reference rule including a resolutionvalue relationship between the current frame and the reference frame;and acquiring the reference frame corresponding to the current frameaccording to the second reference rule.

Specifically, the second reference rule determines a resolution valuelimit relationship between the current frame and the reference frame. Itmay be understood that to ensure that the reference frame acquired inthe encoding process is consistent with the reference frame acquired inthe decoding process, the first reference rule is consistent with thesecond reference rule. The first reference rule and the second referencerule may be preset in a codec standard. Alternatively, during encoding,the first reference rule may be selected according to an applicationscenario, a real-time performance requirement and the like of encoding,and reference rule information is carried in the encoded data. A decoderobtains the second reference rule according to the reference ruleinformation in the encoded data. The resolution value relationshipincludes at least one of the current frame and the reference framehaving the same resolution or different resolutions. If the secondreference rule includes that the current frame and the reference framehave the same resolution, the second reference rule may further includea processing mode reference rule of the resolutions of the current frameand the reference frame. For example, the processing mode reference rulemay include: a reference frame using a full-resolution processing modemay be referenced for a current video frame using a full-resolutionprocessing mode, a reference frame using a down-sampling processing modemay be referenced for a current video frame using a down-samplingprocessing mode, or both. If the second reference rule includes that thecurrent frame and the reference frame have different resolutions, thesecond reference rule may further include: a resolution of the currentframe is greater than a resolution of the reference frame, a resolutionof the current frame is less than a resolution of the reference frame,or both. Therefore, the second reference rule may include one or more ofthat a reference frame with a down-sampled resolution may be referencedfor a current video frame with an original resolution, a reference framewith an original resolution may be referenced for a current frame with adown-sampled resolution, a reference frame with an original resolutionmay be referenced for a current frame with an original resolution, and areference frame with a down-sampled resolution may be referenced for acurrent frame with a down-sampled resolution. The current frame with anoriginal resolution means that a resolution of the current frame is thesame as that of a corresponding input video frame, and the referenceframe with an original resolution means that a resolution of thereference frame is the same as that of an input video framecorresponding to the reference frame. The current frame with adown-sampled resolution means that the resolution informationcorresponding to the current frame is down-sampling. The reference framewith a down-sampled resolution is that resolution informationcorresponding to the reference frame is down-sampling. After the secondreference rule is obtained, the reference frame corresponding to thecurrent frame is obtained according to the second reference rule, sothat the obtained reference frame satisfies the second reference rule.

S1306: Determine a sub-pixel interpolation mode, the sub-pixelinterpolation mode comprising one of a direct sub-pixel interpolationmode and a sampled sub-pixel interpolation mode.

Sub-pixel interpolation is a process of performing interpolation byusing reference data of a whole pixel in a reference frame to obtainreference data on a sub-pixel level. In the decoding process of thecurrent frame, the decoding end needs to decode the encoded data toobtain a motion vector, so as to determine a corresponding position of adecoded block in the current frame in the reference frame according tothe motion vector, decode the encoded data to obtain a residual, adddata at the corresponding position in the reference frame to theresidual to obtain data corresponding to the decoded block, so as toobtain a reconstructed video block. Therefore, sub-pixel interpolationprocessing is performed on the reference frame to obtain the targetreference frame, so that a position corresponding to a decoded block inthe current frame can be accurately found from the target referenceframe with a higher resolution, thereby improving decoding quality.

The sub-pixel interpolation mode is a mode of performing sub-pixelinterpolation processing on the acquired reference frame, includingdirectly performing sub-pixel interpolation processing on the referenceframe and performing sub-pixel interpolation processing after performingsampling processing on the reference frame.

Specifically, if the reference frame and the current frame have the sameresolution, the decoding end may directly perform sub-pixelinterpolation processing on the reference frame. If the reference frameand the current frame have different resolutions, the decoding end mayperform sub-pixel interpolation processing on the reference framedirectly, or may sample the reference frame to obtain a frame with aresolution the same as that of the current frame, and then performsub-pixel interpolation processing on the obtained frame with the sameresolution. The two sub-pixel interpolation modes are applicable. Thesampling of the reference frame includes up-sampling processing anddown-sampling processing. In an embodiment, if there are a plurality ofreference frames, each reference frame is sampled to obtain a framehaving a resolution the same as that of the current frame.

In this embodiment, the reference frame is sampled to obtain a framehaving a resolution the same as that of the current frame, so that animage matching degree between the current frame and the to-be-referencedframe can be somewhat improved, thereby improving the accuracy ofinter-frame prediction, reducing the prediction residual, and improvingthe quality of an decoded image.

In an embodiment, the encoding end and the decoding end may set inrespective codec rules sub-pixel interpolation modes used duringprocessing of the reference frame to obtain a target reference frame.The used sub-pixel interpolation modes are recommended to be consistent.Corresponding sub-pixel interpolation modes of processing the referenceframe are determined according to configurations during encoding anddecoding.

In an embodiment, the decoding end may further acquire sub-pixelinterpolation mode information corresponding to the current frame fromthe header information of the encoded data corresponding to the currentframe. The sub-pixel interpolation mode information is used forindicating a sub-pixel interpolation mode corresponding to theprocessing of the reference frame. The header information comprisessequence header information, group header information or frame headerinformation of the encoded data corresponding to the current frame. Thatis, the decoding end may acquire the sub-pixel interpolation modeinformation corresponding to the current frame from any one of sequenceheader information, group header information, and frame headerinformation. For example, if the flag bit Pixel_Sourse_Interpolationused for determining the sub-pixel interpolation mode in the frameheader information of the encoded data is 0, it indicates that sub-pixelinterpolation processing is directly performed on the reference framecorresponding to the input video frame. If Pixel_Sourse_Interpolation is1, it indicates that sampling processing is performed on the referenceframe corresponding to the input video frame before sub-pixelinterpolation processing is performed. The decoding end may performsub-pixel interpolation processing on the reference frame by using amode the same as the sub-pixel interpolation mode indicated by the flagbit in the encoded data to obtain the target reference frame, so thatthe encoded data may be decoded according to the target reference frameto obtain a reconstructed video frame.

S1308: Process the reference frame according to resolution informationof the current frame using the sub-pixel interpolation mode, to obtain acorresponding target reference frame.

The resolution information of the current frame may be a resolution ofthe current frame or may be down-sampling ratio informationcorresponding to the current frame. Because of the correspondencebetween decoding and encoding, the encoded data corresponding to thecurrent frame is obtained by encoding the current frame. Therefore, theresolution information of the current frame is the same as theresolution information of the current frame. Similarly, the referenceframe corresponding to the current frame is the same as the referenceframe corresponding to the current frame.

The target reference frame is a video frame obtained after sub-pixelinterpolation processing is performed on the reference frame accordingto a corresponding sub-pixel interpolation mode. Specifically, thedecoding end may determine a sampling method corresponding to the usedsub-pixel interpolation mode according to a proportional relationshipbetween a resolution indicated by the resolution information of thecurrent frame and a resolution indicated by the resolution informationof the reference frame, the sampling method including an up-samplingmethod or a down-sampling method.

In an embodiment, the decoding end may determine a ratio for samplingthe reference frame according to the proportional relationship betweenthe resolution of the current frame and the resolution of the referenceframe. For example, if the resolution of the current frame is 2M*2N, andthe resolution of the reference frame corresponding to the current frameis M*2N. In this case, it is determined that up-sampling processing isperformed on the reference frame by using a sampling ratio of a width of1/2 and a height of 1, to obtain a frame with a resolution the same asthat of the current frame. If the resolution of the current frame isM*N, and the resolution of the reference frame corresponding to thecurrent frame is 2M*2N. It is determined that down-sampling processingis performed on the reference frame using a sampling ratio of a width of1/2 and a height of 1/2, to obtain a frame with a resolution the same asthat of the current frame.

In an embodiment, because input video frames generally have the sameresolution, the decoding end may determine a sampling ratiocorresponding to the current frame and a sampling ratio for a referenceframe corresponding to the current frame based on a down-sampling ratiocorresponding to a current frame obtained by down-sampling an inputvideo frame, and a down-sampling ratio corresponding to a referenceframe to be encoded obtained by down-sampling an input video frame thatcan be used as a reference frame. For example, down-sampling processingis performed on the input video frame by using a sampling ratio of 1/2to obtain a current frame, and a sampling ratio corresponding to thecurrent frame is also 1/2, and down-sampling processing is performed onan input video frame that can be used as a reference frame by using asampling ratio of 1/4 to obtain a reference frame to be encoded, so thata down-sampling ratio corresponding to a reference frame reconstructedaccording to the encoded data of the reference frame to be encoded isalso 1/4, and a down-sampling ratio corresponding to the reference framecorresponding to the current frame is also 1/4. According to a multiplerelationship between the down-sampling ratios of the current frame andthe corresponding reference frame, it may be determined that up-samplingprocessing is performed on the reference frame corresponding to thecurrent frame by using a sampling ratio of 2 to obtain a frame with aresolution the same as that of the current frame.

S1310: Decode the encoded data according to the target reference frame,to obtain a reconstructed video frame corresponding to the currentframe.

The reconstructed video frame is a video frame obtained through decodingand reconstruction. It may be understood that resolution informationcorresponding to the reconstructed video frame corresponds to theresolution information of the current frame in the encoding process. Ifthere is no loss of image information in the encoding process, thereconstructed video frame is the same as the current frame. If there isa loss of image information in the encoding process, a differencebetween the reconstructed video frame and the current frame correspondsto a loss value. The encoded data is decoded by using the resolutioninformation corresponding to the current frame. The decoding may includeat least one of prediction, inverse transformation, inversequantization, and entropy decoding, and is specifically determinedaccording to the encoding process. During decoding, for example, thereference frame corresponding to the current frame may be acquired. Thereference frame is processed according to the resolution informationcorresponding to the current frame, to obtain the target referenceframe. A predicted value corresponding to the current frame is obtainedaccording to the target reference frame, and the reconstructed videoframe is obtained according to the prediction residual in the encodeddata and the predicted value. If a target reference block correspondingto a current video block to be decoded in the reference frame isobtained according to the motion vector, the motion vector in theencoded data is transformed according to resolution informationcorresponding to a unit of the motion vector in the encoded data and theresolution information corresponding to the current frame, to obtain atarget motion vector, and a target reference block is obtained accordingto the target motion vector.

Specifically, decoding is performed according to the resolutioninformation corresponding to the current frame during decoding. Afterthe target reference frame is obtained, the reference blockcorresponding to the encoded block in the current frame may be acquiredfrom the target reference frame. The encoded block is decoded accordingto the reference block, to obtain the reconstructed video framecorresponding to the current frame.

By using the foregoing video decoding method, after encoded datacorresponding to a current frame and a reference frame corresponding tothe current frame are acquired, a sub-pixel interpolation mode of thereference frame may be determined, and the reference frame is processedaccording to resolution information of the reference frame by using thesub-pixel interpolation mode, to adjust a resolution of the referenceframe, to obtain a target reference frame. Even if the resolution of thereference frame is different from that of the current frame, thereference frame may be used as a reference frame for the current frame.The current frame is encoded according to the obtained target referenceframe, thereby improving the utilization efficiency of reference frames,so that the accuracy of inter-frame prediction can be improved, aprediction residual can be reduced, and the quality of an encoded imagecan be improved.

As shown in FIG. 15, in an embodiment, step S1308 (found in FIG. 13),processing the reference frame according to resolution information ofthe current frame by using the sub-pixel interpolation mode, to obtain acorresponding target reference frame includes the following steps.

S1502: Acquire motion estimation pixel precision corresponding to thecurrent frame.

S1504: Process the reference frame according to the resolutioninformation of the current frame and the motion estimation pixelprecision by using the sub-pixel interpolation mode, to obtain thecorresponding target reference frame.

Specifically, the decoding end may acquire the resolution information ofthe reference frame, and determine, according to the sub-pixelinterpolation mode used for the current frame, the resolutioninformation of the current frame, the resolution information of thereference frame, and the motion estimation pixel precision correspondingto the current frame, what sampling processing is to be used for thereference frame, a sampling ratio corresponding to the samplingprocessing, and pixel interpolation precision.

In an embodiment, the motion estimation pixel precision is generally 1/2pixel precision, 1/4 pixel precision, or 1/8 pixel precision. Motionestimation with higher precision cannot significantly improve theencoding quality, but causes significant increase in calculationcomplexity.

In an embodiment, the decoding end may configure corresponding motionestimation pixel precision for the current frame according to imagefeature information of the current frame. The image feature informationis, for example, the size, texture information, motion speed, and thelike of the current frame, and various types of image featureinformation may be combined to determine the motion estimation pixelprecision corresponding to the current frame. If the image data carriedin the current frame is more complex and image information is richer,the corresponding motion estimation pixel precision is higher. Forexample, during inter-frame prediction of a P frame, relatively highmotion estimation pixel precision may be used to calculate motionvectors corresponding to encoded blocks in the P frame. Duringinter-frame prediction of a B frame, relatively low motion estimationpixel precision may be used to calculate motion vectors corresponding toencoded blocks in the B frame.

In an embodiment, step S1504 of processing the reference frame accordingto the resolution information of the current frame and the motionestimation pixel precision by using the sub-pixel interpolation mode, toobtain the corresponding target reference frame includes: if thesub-pixel interpolation mode is a sampled sub-pixel interpolation modeand a resolution indicated by the resolution information of the currentframe is less than a resolution of the reference frame, performingdown-sampling processing on the reference frame according to theresolution information of the current frame to obtain an intermediatereference frame, and performing sub-pixel interpolation processing onthe intermediate reference frame according to the motion estimationpixel precision, to obtain the corresponding target reference frame.

Specifically, if the sub-pixel interpolation mode corresponding to thecurrent frame is a sampled sub-pixel interpolation mode, it indicatesthat sampling processing needs to be performed on the reference framefirst, to obtain the intermediate reference frame with a resolution thesame as that of the current frame, and sub-pixel interpolationprocessing is then performed on the intermediate reference frame toobtain the corresponding target reference frame.

As discussed above, if a resolution indicated by the resolutioninformation of the current frame is less than a resolution of thereference frame, the decoding end needs to determine a sampling ratio ofperforming down-sampling on the reference frame according to theproportional relationship between the two resolutions, and performdown-sampling according to the sampling ratio to obtain an intermediatereference frame with a resolution the same as that of the current frame;and then perform sub-pixel interpolation processing on the intermediatereference frame based on the motion estimation pixel precision, toobtain the target reference frame. In addition, in this case, the pixelinterpolation precision is the same as the motion estimation pixelprecision.

For example, down-sampling processing is performed on an input videoframe with a resolution of 2M*2N by using the down-sampling processingmode to obtain a current frame with a resolution of M*N, so that theresolution of the current frame is also M*N. The resolution of thereference frame is 2M*2N (the full-resolution processing mode).Down-sampling processing is performed on the reference frame accordingto a sampling ratio of 1/2 to obtain an intermediate reference framewith a resolution of M*N. If the motion estimation pixel precisioncorresponding to the acquired current frame is 1/2, sub-pixelinterpolation processing is then performed on the intermediate referenceframe according to pixel interpolation precision the same as the motionestimation pixel precision, that is, sub-pixel interpolation precisionof 1/2, to obtain the target reference frame. If the motion estimationpixel precision corresponding to the acquired current frame is 1/4,sub-pixel interpolation processing is performed on the intermediatereference frame according to the sub-pixel interpolation precision of1/4, to obtain the target reference frame with a higher resolution.

Certainly, the reference frame may also be obtained by using thedown-sampling processing mode. For example, down-sampling processing isperformed on the input video frame with a resolution of 2M*2N accordingto the down-sampling processing mode to obtain a current frame with aresolution of 1/2M*1/2N, so that the resolution of the current frame isalso 1/2M*1/2N. The reference frame is obtained through reconstructionafter down-sampling processing is performed on an input video frame witha resolution of 2M*2N to obtain encoded data corresponding to areference frame to be encoded with a resolution of M*N. In this case,the resolution of the reference frame is also M*N. Therefore, theresolution of the current frame is less than the resolution of thereference frame. Down-sampling processing may be performed on thereference frame according to a sampling ratio of 1/2 to obtain anintermediate reference frame with a resolution the same as that of thecurrent frame. Sub-pixel interpolation processing is then performedbased on the motion estimation pixel precision to obtain the targetreference frame.

In an embodiment, step S1504 of processing the reference frame accordingto the resolution information of the current frame and the motionestimation pixel precision by using the sub-pixel interpolation mode, toobtain the corresponding target reference frame includes: if thesub-pixel interpolation mode is a direct sub-pixel interpolation modeand a resolution indicated by the resolution information of the currentframe is less than a resolution of the reference frame, calculating thepixel interpolation precision according to the resolution information ofthe current frame and the motion estimation pixel precision, anddirectly performing sub-pixel interpolation processing on the referenceframe according to the pixel interpolation precision, to obtain thecorresponding target reference frame.

Specifically, if the sub-pixel interpolation mode corresponding to thecurrent frame is a direct sub-pixel interpolation mode, it indicatesthat sub-pixel interpolation processing may be directly performed on thereference frame to obtain the target reference frame. It may beunderstood that because the resolution of the reference frame is greaterthan the resolution of the current frame, data of some sub-pixels in thereference frame may be directly reused, and may be used as datacorresponding to sub-pixels corresponding to the motion estimation pixelprecision.

For the foregoing process of directly performing sub-pixel interpolationprocessing on the reference frame to obtain the target reference frame,reference may be made to the foregoing description of step S1308.Details are not described herein again.

In an embodiment, step S1504 of processing the reference frame accordingto the resolution information of the current frame and the motionestimation pixel precision using the sub-pixel interpolation mode, toobtain the corresponding target reference frame includes: if thesub-pixel interpolation mode is a sampled sub-pixel interpolation modeand a resolution indicated by the resolution information of the currentframe is greater than a resolution of the reference frame, performingup-sampling processing on the reference frame according to theresolution information of the current frame to obtain an intermediatereference frame, and performing sub-pixel interpolation processing onthe intermediate reference frame according to the motion estimationpixel precision, to obtain the corresponding target reference frame.

As discussed above, if the resolution of the current frame is greaterthan the resolution of the reference frame, the decoding end needs toperform up-sampling processing on the reference frame to obtain theintermediate reference frame with a resolution the same as that of thecurrent frame; and then perform sub-pixel interpolation processing onthe intermediate reference frame based on the motion estimation pixelprecision corresponding to the current frame, to obtain the targetreference frame.

For example, the resolution of the current frame is 2M*2N, and theresolution of the reference frame is 1/2M*1/2N. Up-sampling processingneeds to be performed on the reference frame according to a samplingratio of 1/4 to obtain an intermediate reference frame with a resolutionthe same as that of the current frame. If the motion estimation pixelprecision is 1/2, sub-pixel interpolation processing continues to beperformed on the obtained intermediate reference frame according to thepixel interpolation precision of 1/2, to obtain the target referenceframe. If the motion estimation pixel precision is 1/4, sub-pixelinterpolation processing continues to be performed on the obtainedintermediate reference frame according to the pixel interpolationprecision of 1/4, to obtain the target reference frame.

In an embodiment, step S1504 of processing the reference frame accordingto the resolution information of the current frame and the motionestimation pixel precision using the sub-pixel interpolation mode, toobtain the corresponding target reference frame includes: if thesub-pixel interpolation mode is a direct sub-pixel interpolation modeand a resolution indicated by the resolution information of the currentframe is the same as a resolution of the reference frame, directlyperforming sub-pixel interpolation processing on the reference frameaccording to the motion estimation pixel precision, to obtain thecorresponding target reference frame.

Specifically, the input video frame is processed by using thefull-resolution processing mode to obtain a current frame, so that theresolution of the current frame is also the original resolution, and ifthe resolution of the reference frame is also the original resolution,the resolution of the current frame is the same as the resolution of thereference frame. Alternatively, the input video frame is processed byusing the down-sampling mode to obtain a current frame, and if thereference frame is also reconstructed through the encoded data obtainedby performing encoding by using the down-sampling mode with the samesampling ratio, the resolution of the current frame is the same as theresolution of the reference frame. In this case, the decoding end maydirectly perform sub-pixel interpolation processing on the referenceframe based on the motion estimation pixel precision to obtain thetarget reference frame, and the pixel interpolation precisioncorresponding to the sub-pixel interpolation processing is the same asthe motion estimation pixel precision.

In the foregoing embodiment, sub-pixel interpolation processing isperformed on the reference frame, so that the resolution of thereference frame is higher. In this way, the calculated video frame to bedecoded is more precise than the motion vector of the reference frame,thereby further reducing a prediction residual, so that encoding qualitycan be improved.

In an embodiment, as shown in FIG. 16, step S1310 of decoding theencoded data according to the target reference frame, to obtain areconstructed video frame corresponding to the current frame includesthe following steps.

S1602: Determine a third vector transformation parameter according toresolution information corresponding to the current frame and firstresolution information, the first resolution information includingtarget motion vector unit resolution information.

Specifically, the third vector transformation parameter is used fortransforming a motion vector or position information of the motionvector. The third vector transformation parameter may be a ratio of thefirst resolution information to the resolution information of thecurrent frame to be decoded and may be obtained by dividing theresolution information of the current frame by the first resolutioninformation, or may be obtained by dividing the first resolutioninformation by the resolution information of the current frame, or maybe obtained by multiplying the ratio by a corresponding coefficient oradding a preset offset to the proportion after the proportion isobtained. For example, assuming that the down-sampling ratio of thereference frame is 1/3, the down-sampling ratio of the current frame is1/6. The third vector transformation parameter may be 2 obtained bydividing 1/6 by 1/3. It may be understood that because of thecorrespondence between decoding and encoding, the step of determining athird vector transformation parameter according to resolutioninformation corresponding to the current frame and first resolutioninformation is an inverse process of the step of determining a firstvector transformation parameter according to the resolution informationof the current frame and the first resolution information. For example,assuming that the down-sampling ratio of the reference frame is 1/3, thedown-sampling ratio of the current frame is 1/6. The first vectortransformation parameter may be 2 obtained by dividing 1/3 by 1/6. Inthis way, in the decoding process, because the current frame is a videoframe obtained after encoding the current frame, the down-sampling ratioof the reference frame is also 1/3, and the down-sampling ratiocorresponding to the current frame is 1/6, so that the third vectortransformation parameter is equal to 2 obtained by dividing 1/3 by 1/6.

S1604: Acquire a target motion vector corresponding to each video blockto be decoded in the current frame according to the encoded data.

Specifically, if the encoded data carries the target motion vector, thetarget motion vector is read from the encoded data. If the encoded datacarries a motion vector difference, a target predicted motion vector maybe calculated, and the target motion vector is obtained according to themotion vector difference and the target predicted motion vector.

S1606: Obtain a reference image block corresponding to each video blockto be decoded in the current frame according to the third vectortransformation parameter and the target motion vector.

Specifically, after the third vector transformation parameter isobtained, the obtained motion vector or the position informationcorresponding to the motion vector is transformed according to the thirdvector transformation parameter to obtain position informationcorresponding to the reference image block, so as to obtain thereference image block.

S1608: Decode the encoded data according to the reference image block,to obtain a reconstructed video frame corresponding to the currentframe.

Specifically, after the reference image block is obtained, a pixel valueof each image block in the reconstructed video frame is obtainedaccording to a pixel value of the reference image block and theprediction residual of the video block to be decoded carried in theencoded data, to obtain the reconstructed video frame.

In an embodiment, step S1602 of determining a third vectortransformation parameter according to resolution informationcorresponding to the current frame and first resolution informationincludes: determining a third vector transformation parameter accordingto the resolution information corresponding to the current frame andresolution information of the reference frame; and step S1606 ofobtaining a reference image block corresponding to each video block tobe decoded in the current frame according to the third vectortransformation parameter and the target motion vector includes:acquiring first position information corresponding to the current videoblock to be decoded; and obtaining a target reference image blockcorresponding to the current video block to be decoded according to thefirst position information, the third vector transformation parameter,and the target motion vector.

Specifically, second position information corresponding to the targetreference image block may be obtained according to the first positioninformation, the third vector transformation parameter, and the targetmotion vector, and the target reference image block is obtainedaccording to the second position information. Because of thecorrespondence between encoding and decoding, the process of determininga third vector transformation parameter according to resolutioninformation corresponding to the current frame and first resolutioninformation is an inverse process of determining a first vectortransformation parameter according to the resolution information of thecurrent frame and the resolution information of the reference frame.

In an embodiment, if the first vector transformation parameter is aproportion obtained by dividing high resolution information by lowresolution information in the resolution information of the currentframe and the resolution information of the reference frame, the thirdvector transformation parameter may be a proportion obtained by dividingthe low resolution information by the high resolution information in theresolution information of the current frame and the resolutioninformation of the reference frame. A resolution corresponding to thehigh resolution information is greater than a resolution correspondingto the low resolution information. The third vector transformationparameter is used for transforming position information of the framewith the low resolution information in the current frame and thereference frame. For example, the resolution of the current frame is1200*1200 pixels, and the resolution of the reference frame is 600*600pixels, so that the high resolution is 1200*1200 pixels, and the lowresolution is 600*600 pixels. The third vector transformation parametermay be 1/2. Assuming that the first position information is (6, 8) andthe target motion vector is (0, 2), the intermediate positioninformation is (6, 8)−(0, 2)=(6, 6), and the second position informationcorresponding to the target reference block is (6*1/2, 6*1/2)=(3, 3).

In an embodiment, step S1602 of determining a third vectortransformation parameter according to resolution informationcorresponding to the current frame and first resolution informationincludes: determining a third vector transformation parameter accordingto the resolution information corresponding to the current frame and thetarget motion vector unit resolution information; and step S1604 ofobtaining a reference image block corresponding to each video block tobe decoded in the current frame according to the third vectortransformation parameter and the target motion vector includes:obtaining a first motion vector according to the target motion vectorand the third vector transformation parameter; and acquiring the targetreference image block corresponding to the current video block to bedecoded according to the first motion vector.

Specifically, the third vector transformation parameter is determinedaccording to the resolution information corresponding to the currentframe and the target motion vector unit resolution information. Afterthe third vector transformation parameter is obtained, the third vectortransformation parameter may be multiplied by the target motion vectorto use the obtained product as the first motion vector. It may beunderstood that the process of obtaining a first motion vector accordingto the third vector transformation parameter and the target motionvector is an inverse process of obtaining a target motion vectorcorresponding to the current encoded block according to the first vectortransformation parameter and the first motion vector. For example, thefirst vector transformation parameter is equal to 2. The obtained firstmotion vector is (2, 2), and the target motion vector obtained accordingto the product of multiplying the first vector transformation parameterby the first motion vector of (2, 2) is (4, 4). In the decoding process,the third vector transformation parameter is 1/2, the obtained targetmotion vector is (4, 4), and the first motion vector obtained accordingto the product of multiplying the third vector transformation parameterof 1/2 by the target motion vector of (4, 4) is (2, 2).

In an embodiment, if the encoded data carries the motion vectordifference, the acquiring a target motion vector corresponding to eachvideo block to be decoded in the current frame according to the encodeddata includes: acquiring a motion vector difference corresponding to acurrent video block to be decoded in the current frame according to theencoded data; and

acquiring an initial predicted motion vector corresponding to thecurrent video block to be decoded; obtaining the second vectortransformation coefficient according to current motion vector unitresolution information corresponding to the initial predicted motionvector and the target motion vector unit resolution information;obtaining a target predicted motion vector corresponding to the currentvideo block to be decoded according to the initial predicted motionvector and the second vector transformation coefficient; and obtainingthe target motion vector according to the target predicted motion vectorand the motion vector difference.

Specifically, because a video block to be decoded corresponds to a videoblock to be encoded in the decoding process and the encoding process,the same acquisition rule is used for the initial predicted motionvector. Therefore, the initial predicted motion vector corresponding tothe current video block to be decoded is consistent with the initialpredicted motion vector corresponding to the current video block to beencoded. For the method for obtaining the target predicted motionvector, reference may be made to the method in the encoding process.Details are not described again. The target motion vector may be a sumof the target predicted motion vector and the motion vector difference.

As shown in FIG. 17, in an embodiment, a video encoding apparatus 1700is provided. The video encoding apparatus 1700 specifically includes areference frame acquisition module 1702, a sub-pixel interpolation modedetermination module 1704, a target reference frame determination module1706, and an encoded data obtaining module 1708.

The reference frame acquisition module 1702 is configured to acquire areference frame corresponding to a current frame to be encoded from avideo input.

The sub-pixel interpolation mode determination module 1704 is configuredto determine a sub-pixel interpolation mode, the sub-pixel interpolationmode comprising one of a direct sub-pixel interpolation mode and asampled sub-pixel interpolation mode.

The target reference frame determination module 1706 is configured toprocess the reference frame according to resolution information of thecurrent frame by using the sub-pixel interpolation mode, to obtain acorresponding target reference frame.

The encoded data obtaining module 1708 is configured to encode thecurrent frame according to the target reference frame, to obtain encodeddata corresponding to the current frame.

In an embodiment, the target reference frame determination module 1706is further configured to: acquire motion estimation pixel precisioncorresponding to the current frame; and process the reference frameaccording to the resolution information of the current frame and themotion estimation pixel precision by using the sub-pixel interpolationmode, to obtain the corresponding target reference frame.

In an embodiment, the target reference frame determination module 1706is further configured to: if the sub-pixel interpolation mode is asampled sub-pixel interpolation mode and a resolution indicated by theresolution information of the current frame is less than a resolution ofthe reference frame, perform down-sampling processing on the referenceframe according to the resolution information of the current frame toobtain an intermediate reference frame, and perform sub-pixelinterpolation processing on the intermediate reference frame accordingto the motion estimation pixel precision, to obtain the correspondingtarget reference frame.

In an embodiment, the target reference frame determination module 1706is further configured to: if the sub-pixel interpolation mode is adirect sub-pixel interpolation mode and a resolution indicated by theresolution information of the current frame is less than a resolution ofthe reference frame, calculate pixel interpolation precision accordingto the resolution information of the current frame and the motionestimation pixel precision, and directly perform sub-pixel interpolationprocessing on the reference frame according to the pixel interpolationprecision, to obtain the corresponding target reference frame.

In an embodiment, the target reference frame determination module 1706is further configured to: if the sub-pixel interpolation mode is asampled sub-pixel interpolation mode and a resolution indicated by theresolution information of the current frame is greater than a resolutionof the reference frame, perform up-sampling processing on the referenceframe according to the resolution information of the current frame toobtain an intermediate reference frame, and perform sub-pixelinterpolation processing on the intermediate reference frame accordingto the motion estimation pixel precision, to obtain the correspondingtarget reference frame.

In an embodiment, the target reference frame determination module 1706is further configured to: if the sub-pixel interpolation mode is adirect sub-pixel interpolation mode and a resolution indicated by theresolution information of the current frame is the same as a resolutionof the reference frame, directly perform sub-pixel interpolationprocessing on the reference frame according to the motion estimationpixel precision, to obtain the corresponding target reference frame.

In an embodiment, the encoded data obtaining module 1708 is furtherconfigured to add the sub-pixel interpolation mode corresponding to theprocessing of the reference frame to the encoded data corresponding tothe current frame.

By using the foregoing video encoding apparatus 1700, after a referenceframe corresponding to a current frame is acquired, a sub-pixelinterpolation mode of the reference frame may be determined, and thereference frame is processed according to resolution information of thereference frame by using the sub-pixel interpolation mode, to adjust aresolution of the reference frame, and obtain a target reference frame.Even if the resolution of the reference frame is different from that ofthe current frame, the reference frame may be used as a reference framefor the current frame. The current frame is encoded according to theobtained target reference frame, thereby improving the utilizationefficiency of reference frames, so that the accuracy of inter-frameprediction can be improved, a prediction residual can be reduced, andthe quality of an encoded image can be improved.

As shown in FIG. 18, in an embodiment, a video decoding apparatus 1800is provided. The video decoding apparatus 1800 specifically includes anencoded data acquisition module 1802, a reference frame acquisitionmodule 1804, a sub-pixel interpolation mode determination module 1806, atarget reference frame determination module 1808, and a reconstructedvideo frame obtaining module 1810.

The encoded data acquisition module 1802 is configured to acquireencoded data corresponding to a current frame to be decoded.

The reference frame acquisition module 1804 is configured to acquire areference frame corresponding to the current frame.

The sub-pixel interpolation mode determination module 1806 is configuredto determine a sub-pixel interpolation mode, the sub-pixel interpolationmode comprising one of a direct sub-pixel interpolation mode and asampled sub-pixel interpolation mode.

The target reference frame determination module 1808 is configured toprocess the reference frame according to resolution information of thecurrent frame by using the sub-pixel interpolation mode, to obtain acorresponding target reference frame.

The reconstructed video frame obtaining module 1810 is configured todecode the encoded data according to the target reference frame, toobtain a reconstructed video frame corresponding to the current frame.

In an embodiment, the target reference frame determination module 1808is further configured to: acquire motion estimation pixel precisioncorresponding to the current frame; and process the reference frameaccording to the resolution information of the current frame and themotion estimation pixel precision by using the sub-pixel interpolationmode, to obtain the corresponding target reference frame.

In an embodiment, the target reference frame determination module 1808is further configured to: if the sub-pixel interpolation mode is asampled sub-pixel interpolation mode and a resolution indicated by theresolution information of the current frame is less than a resolution ofthe reference frame, perform down-sampling processing on the referenceframe according to the resolution information of the current frame toobtain an intermediate reference frame, and perform sub-pixelinterpolation processing on the intermediate reference frame accordingto the motion estimation pixel precision, to obtain the correspondingtarget reference frame.

In an embodiment, the target reference frame determination module 1808is further configured to: if the sub-pixel interpolation mode is adirect sub-pixel interpolation mode and a resolution indicated by theresolution information of the current frame is less than a resolution ofthe reference frame, calculate the pixel interpolation precisionaccording to the resolution information of the current frame and themotion estimation pixel precision, and directly perform sub-pixelinterpolation processing on the reference frame according to the pixelinterpolation precision, to obtain the corresponding target referenceframe.

In an embodiment, the target reference frame determination module 1808is further configured to: if the sub-pixel interpolation mode is asampled sub-pixel interpolation mode and a resolution indicated by theresolution information of the current frame is greater than a resolutionof the reference frame, perform up-sampling processing on the referenceframe according to the resolution information of the current frame toobtain an intermediate reference frame, and perform sub-pixelinterpolation processing on the intermediate reference frame accordingto the motion estimation pixel precision, to obtain the correspondingtarget reference frame.

In an embodiment, the target reference frame determination module 1808is further configured to: if the sub-pixel interpolation mode is adirect sub-pixel interpolation mode and a resolution indicated by theresolution information of the current frame is the same as a resolutionof the reference frame, directly perform sub-pixel interpolationprocessing on the reference frame according to the motion estimationpixel precision, to obtain the corresponding target reference frame.

By using the foregoing video decoding apparatus 1800, after encoded datacorresponding to a current frame and a reference frame corresponding tothe current frame are acquired, a sub-pixel interpolation mode of thereference frame may be determined, and the reference frame is processedaccording to resolution information of the reference frame by using thesub-pixel interpolation mode, to adjust a resolution of the referenceframe, to obtain a target reference frame. Even if the resolution of thereference frame is different from that of the current frame, thereference frame may be used as a reference frame for the current frame.The current frame is encoded according to the obtained target referenceframe, thereby improving the utilization efficiency of reference frames,so that the accuracy of inter-frame prediction can be improved, aprediction residual can be reduced, and the quality of an encoded imagecan be improved.

FIG. 19 is a diagram of an internal structure of a computer deviceaccording to an embodiment. The computer device may be specifically theterminal 110 in FIG. 1. As shown in FIG. 19, the computer deviceincludes a processor, a memory, a network interface, an input apparatus,and a display screen that are connected by using a system bus. Thememory includes a non-transitory storage medium and an internal memory.The non-transitory storage medium of the computer device stores anoperating system, and may further store a computer program. The computerprogram, when being executed by the processor, may cause the processorto implement at least one of the video encoding method and the videodecoding method described in this disclosure. The internal memory mayalso store a computer program. When being executed by the processor, thecomputer program may cause the processor to perform at least one of thevideo encoding method and the video decoding method. The display screenof the computer device may be a liquid crystal display screen or ane-ink display screen. The input apparatus of the computer device may bea touch layer covering the display screen, or may be a button, atrackball, or a touchpad disposed on a housing of the computer device,or may be an external keyboard, touchpad, a mouse or the like.

FIG. 20 is a diagram of an internal structure of a computer deviceaccording to an embodiment. The computer device may be specifically theserver 120 in FIG. 1. As shown in FIG. 20, the computer device includesa processor, a memory, a network interface, an input apparatus, and adisplay screen that are connected by using a system bus. The memoryincludes a non-transitory storage medium and an internal memory. Thenon-transitory storage medium of the computer device stores an operatingsystem, and may further store a computer program. The computer program,when being executed by the processor, may cause the processor toimplement at least one of the video encoding method and the videodecoding method. The internal memory may also store a computer program.When being executed by the processor, the computer program may cause theprocessor to perform at least one of the video encoding method and thevideo decoding method described in this disclosure. The display screenof the computer device may be a liquid crystal display screen or ane-ink display screen. The input apparatus of the computer device may bea touch layer covering the display screen, or may be a button, atrackball, or a touchpad disposed on a housing of the computer device,or may be an external keyboard, touchpad, a mouse or the like.

A person skilled in the art may understand that, the structure shown inFIG. 19 and FIG. 20 is merely a block diagram of a partial structurerelated to a solution in this application, and does not constitute alimitation to the computer device to which the solution in thisapplication is applied. Specifically, the computer device may includemore or fewer components than those shown in the figure, or have somecomponents combined, or have a different component deployment.

In an embodiment, the video encoding apparatus 1700 provided in thisapplication may be implemented in the form of a computer program. Thecomputer program may run on the computer device shown in FIG. 19 andFIG. 20. The memory of the computer device may store program modulesforming the video encoding apparatus, for example, the reference frameacquisition module 1702, the sub-pixel interpolation mode determinationmodule 1704, the target reference frame determination module 1706, andthe encoded data obtaining module 1708 shown in FIG. 17. The computerprogram formed by the various program modules causes the processor toperform the steps of the video encoding method described in theembodiments of this application in this specification.

For example, the computer device shown in FIG. 19 and FIG. 20 mayperform step S202 by using the reference frame acquisition module 1702in the video encoding apparatus 1700 shown in FIG. 17. The computerdevice may perform step S204 by using the sub-pixel interpolation modedetermination module 1704. The computer device may perform step S206 byusing the target reference frame determination module 1706. The computerdevice may perform step S208 by using the encoded data obtaining module1708.

In an embodiment, the video decoding apparatus 1800 provided in thisapplication may be implemented in the form of a computer program. Thecomputer program may run on the computer device shown in FIG. 19 andFIG. 20. The memory of the computer device may store program modulesforming the video decoding apparatus, for example, the encoded dataacquisition module 1802, the reference frame acquisition module 1804,the sub-pixel interpolation mode determination module 1806, the targetreference frame determination module 1808, and the reconstructed videoframe obtaining module 1810 shown in FIG. 16. The computer programformed by the various program modules causes the processor to performthe steps of the video encoding method described in the embodiments ofthis application in this specification.

For example, the computer device shown in FIG. 19 and FIG. 20 mayperform step S1302 by using the encoded data acquisition module 1802 inthe video decoding apparatus 1800 shown in FIG. 18. The computer devicemay perform step S1304 by using the reference frame acquisition module1804. The computer device may perform step S1306 by using the sub-pixelinterpolation mode determination module 1806. The computer device mayperform step S1308 by using the target reference frame determinationmodule 1808. The computer device may perform step S1310 by using thereconstructed video frame obtaining module 1810.

In an embodiment, a computer device is provided, including a memory anda processor, the memory storing a computer program, the computerprogram, when being executed by the processor, implementing the videoencoding method or the video decoding method provided in the foregoingembodiments.

By using the foregoing computer device, after a reference framecorresponding to a current frame is acquired, a sub-pixel interpolationmode of the reference frame may be determined, and the reference frameis processed according to resolution information of the reference frameby using the sub-pixel interpolation mode, to adjust a resolution of thereference frame, to obtain a target reference frame. Even if theresolution of the reference frame is different from that of the currentframe, the reference frame may be used as a reference frame for thecurrent frame. The current frame is encoded according to the obtainedtarget reference frame, thereby improving the utilization efficiency ofreference frames, so that the accuracy of inter-frame prediction can beimproved, a prediction residual can be reduced, and the quality of anencoded image can be improved.

By using the foregoing computer device, after encoded data correspondingto a current frame and a reference frame corresponding to the currentframe are acquired, a sub-pixel interpolation mode of the referenceframe may be determined, and the reference frame is processed accordingto resolution information of the reference frame by using the sub-pixelinterpolation mode, to adjust a resolution of the reference frame, toobtain a target reference frame. Even if the resolution of the referenceframe is different from that of the current frame, the reference framemay be used as a reference frame for the current frame. The currentframe is encoded according to the obtained target reference frame,thereby improving the utilization efficiency of reference frames, sothat the accuracy of inter-frame prediction can be improved, aprediction residual can be reduced, and the quality of an encoded imagecan be improved.

In an embodiment, a computer-readable storage medium is provided,storing a computer program, the computer program, when being executed bythe processor, implementing the video encoding method or the videodecoding method provided in the foregoing embodiments.

By using the foregoing computer-readable storage medium, after areference frame corresponding to a current frame is acquired, asub-pixel interpolation mode of the reference frame may be determined,and the reference frame is processed according to resolution informationof the reference frame by using the sub-pixel interpolation mode, toadjust a resolution of the reference frame, to obtain a target referenceframe. Even if the resolution of the reference frame is different fromthat of the current frame, the reference frame may be used as areference frame for the current frame. The current frame is encodedaccording to the obtained target reference frame, thereby improving theutilization efficiency of reference frames, so that the accuracy ofinter-frame prediction can be improved, a prediction residual can bereduced, and the quality of an encoded image can be improved.

By using the foregoing computer-readable storage medium, after encodeddata corresponding to a current frame and a reference framecorresponding to the current frame are acquired, a sub-pixelinterpolation mode of the reference frame may be determined, and thereference frame is processed according to resolution information of thereference frame by using the sub-pixel interpolation mode, to adjust aresolution of the reference frame, to obtain a target reference frame.Even if the resolution of the reference frame is different from that ofthe current frame, the reference frame may be used as a reference framefor the current frame. The current frame is encoded according to theobtained target reference frame, thereby improving the utilizationefficiency of reference frames, so that the accuracy of inter-frameprediction can be improved, a prediction residual can be reduced, andthe quality of an encoded image can be improved.

A person of ordinary skill in the art may understand that all or some ofthe processes of the methods in the foregoing embodiments may beimplemented by a computer program instructing relevant hardware. Theprogram may be stored in a non-transitory computer-readable storagemedium. When the program runs, the processes of the foregoing methods inthe embodiments may be performed. Any reference to a memory, a storage,a database, or another medium used in the various embodiments providedin this application can include a non-transitory and/or volatile memory.The non-transitory memory may include a read-only memory (ROM), aprogrammable ROM (PROM), an electrically programmable ROM (EPROM), anelectrically erasable programmable ROM (EEPROM) or a flash memory. Thevolatile memory may include a random access memory (RAM) or an externalcache. As an illustration instead of a limitation, the RAM is availablein various forms, such as a static RAM (SRAM), a dynamic RAM (DRAM), asynchronous DRAM (SDRAM), a double data rate SDRAM (DDRSDRAM), anenhanced SDRAM (ESDRAM), a synchronous link (Synchlink) DRAM (SLDRAM), arambus direct RAM (RDRAM), a direct rambus dynamic RAM (DRDRAM), and arambus dynamic RAM (DRAM).

The technical features in the foregoing embodiments may be randomlycombined. For concise description, not all possible combinations of thetechnical features in the embodiment are described. However, thecombinations of the technical features shall all be considered asfalling within the scope recorded in this specification provided thatthey do not conflict with each other.

The foregoing embodiments only describe several implementations of thisapplication, and are described in detail, but they shall not beconstrued as a limitation to the patent scope of this application. Aperson of ordinary skill in the art may further make variations andimprovements without departing from the ideas of this application, whichshall fall within the protection scope of this application. Therefore,the protection scope of this application shall be subject to theprotection scope of the appended claims.

What is claimed is:
 1. A method for video encoding, performed by acomputer device, comprising: acquiring a reference frame correspondingto a current frame to be encoded from a video input; determining asub-pixel interpolation mode, the sub-pixel interpolation modecomprising one of a direct sub-pixel interpolation mode or a sampledsub-pixel interpolation mode; processing the reference frame accordingto resolution information of the current frame using an interpolation inthe sub-pixel interpolation mode, to obtain a corresponding targetreference frame; and encoding the current frame according to the targetreference frame, to obtain encoded data corresponding to the currentframe.
 2. The method according to claim 1, wherein processing thereference frame to obtain the corresponding target reference framecomprises: acquiring motion estimation pixel precision corresponding tothe current frame; and processing the reference frame according to theresolution information of the current frame and the motion estimationpixel precision using the sub-pixel interpolation mode, to obtain thecorresponding target reference frame.
 3. The method according to claim2, wherein processing the reference frame according to the resolutioninformation of the current frame and the motion estimation pixelprecision using the sub-pixel interpolation mode, to obtain thecorresponding target reference frame comprises: when the sub-pixelinterpolation mode is a sampled sub-pixel interpolation mode and aresolution indicated by the resolution information of the current frameis less than a resolution of the reference frame: performingdown-sampling processing on the reference frame according to theresolution information of the current frame to obtain an intermediatereference frame; and performing sub-pixel interpolation processing onthe intermediate reference frame according to the motion estimationpixel precision, to obtain the corresponding target reference frame. 4.The method according to claim 2, wherein processing the reference frameaccording to the resolution information of the current frame and themotion estimation pixel precision using the sub-pixel interpolationmode, to obtain the corresponding target reference frame comprises: whenthe sub-pixel interpolation mode is a direct sub-pixel interpolationmode and a resolution indicated by the resolution information of thecurrent frame is less than a resolution of the reference frame:calculating pixel interpolation precision according to the resolutioninformation of the current frame and the motion estimation pixelprecision; and performing sub-pixel interpolation processing on thereference frame directly according to the pixel interpolation precision,to obtain the corresponding target reference frame.
 5. The methodaccording to claim 2, wherein processing the reference frame accordingto the resolution information of the current frame and the motionestimation pixel precision using the sub-pixel interpolation mode, toobtain the corresponding target reference frame comprises: when thesub-pixel interpolation mode is a sampled sub-pixel interpolation modeand a resolution indicated by the resolution information of the currentframe is greater than a resolution of the reference frame: performingup-sampling processing on the reference frame according to theresolution information of the current frame to obtain an intermediatereference frame; and performing sub-pixel interpolation processing onthe intermediate reference frame according to the motion estimationpixel precision, to obtain the corresponding target reference frame. 6.The method according to claim 2, wherein processing the reference frameaccording to the resolution information of the current frame and themotion estimation pixel precision using the sub-pixel interpolationmode, to obtain the corresponding target reference frame comprises: whenthe sub-pixel interpolation mode is a direct sub-pixel interpolationmode and a resolution indicated by the resolution information of thecurrent frame is the same as a resolution of the reference frame,performing sub-pixel interpolation processing on the reference framedirectly according to the motion estimation pixel precision, to obtainthe corresponding target reference frame.
 7. The method according toclaim 1, further comprising: adding information associated with thesub-pixel interpolation mode corresponding to the processing of thereference frame to the encoded data corresponding to the current frame.8. The method according to claim 7, wherein adding informationassociated with the sub-pixel interpolation mode to the encoded datacomprises: adding the information associated with the sub-pixelinterpolation mode into header information of the encoded datacorresponding to the current frame, the sub-pixel interpolation modeinformation being used for indicating a sub-pixel interpolation modecorresponding to the processing of the reference frame.
 9. The methodaccording to claim 8, wherein the header information comprises sequenceheader information, group header information, or frame headerinformation of the encoded data corresponding to the current frame. 10.A method for video decoding, comprising: acquiring encoded datacorresponding to a current frame to be decoded from a video input;acquiring a reference frame corresponding to the current frame;determining a sub-pixel interpolation mode, the sub-pixel interpolationmode comprising one of a direct sub-pixel interpolation mode or asampled sub-pixel interpolation mode; processing the reference frameaccording to resolution information of the current frame using thesub-pixel interpolation mode, to obtain a corresponding target referenceframe; and decoding the encoded data according to the target referenceframe, to obtain a reconstructed video frame corresponding to thecurrent frame.
 11. The method according to claim 10, wherein processingthe reference frame to obtain the corresponding target reference framecomprises: acquiring motion estimation pixel precision corresponding tothe current frame; and processing the reference frame according to theresolution information of the current frame and the motion estimationpixel precision using the sub-pixel interpolation mode, to obtain thecorresponding target reference frame.
 12. The method according to claim11, wherein processing the reference frame according to the resolutioninformation of the current frame and the motion estimation pixelprecision using the sub-pixel interpolation mode, to obtain thecorresponding target reference frame comprises: when the sub-pixelinterpolation mode is a sampled sub-pixel interpolation mode and aresolution indicated by the resolution information of the current frameis less than a resolution of the reference frame: performingdown-sampling processing on the reference frame according to theresolution information of the current frame to obtain an intermediatereference frame; and performing sub-pixel interpolation processing onthe intermediate reference frame according to the motion estimationpixel precision, to obtain the corresponding target reference frame. 13.The method according to claim 11, wherein processing the reference frameaccording to the resolution information of the current frame and themotion estimation pixel precision using the sub-pixel interpolationmode, to obtain the corresponding target reference frame comprises: whenthe sub-pixel interpolation mode is a direct sub-pixel interpolationmode and a resolution indicated by the resolution information of thecurrent frame is less than a resolution of the reference frame:calculating pixel interpolation precision according to the resolutioninformation of the current frame and the motion estimation pixelprecision; and performing sub-pixel interpolation processing on thereference frame directly according to the pixel interpolation precision,to obtain the corresponding target reference frame.
 14. The methodaccording to claim 11, wherein processing the reference frame accordingto the resolution information of the current frame and the motionestimation pixel precision using the sub-pixel interpolation mode, toobtain the corresponding target reference frame comprises: when thesub-pixel interpolation mode is a sampled sub-pixel interpolation modeand a resolution indicated by the resolution information of the currentframe is greater than a resolution of the reference frame, performingup-sampling processing on the reference frame according to theresolution information of the current frame to obtain an intermediatereference frame; and performing sub-pixel interpolation processing onthe intermediate reference frame according to the motion estimationpixel precision, to obtain the corresponding target reference frame. 15.The method according to claim 11, wherein processing the reference frameaccording to the resolution information of the current frame and themotion estimation pixel precision using the sub-pixel interpolationmode, to obtain the corresponding target reference frame comprises: whenthe sub-pixel interpolation mode is a direct sub-pixel interpolationmode and a resolution indicated by the resolution information of thecurrent frame is the same as a resolution of the reference frame,performing sub-pixel interpolation processing on the reference framedirectly according to the motion estimation pixel precision, to obtainthe corresponding target reference frame.
 16. The method according toclaim 10, wherein determining the sub-pixel interpolation mode furthercomprises: acquiring sub-pixel interpolation mode information fromheader information of the encoded data corresponding to the currentframe, the sub-pixel interpolation mode information being used forindicating a sub-pixel interpolation mode corresponding to theprocessing of the reference frame.
 17. The method according to claim 16,wherein the header information comprises sequence header information,group header information, or frame header information of the encodeddata corresponding to the current frame.
 18. An apparatus for videoencoding, comprising one of a memory for storing computer readableinstructions and a processor in communication with the memory, whereinthe processor is configured to execute the computer readableinstructions to cause the apparatus to: acquire a reference framecorresponding to a current frame to be encoded from a video input;determine a sub-pixel interpolation mode, the sub-pixel interpolationmode comprising one of a direct sub-pixel interpolation mode or asampled sub-pixel interpolation mode; process the reference frameaccording to resolution information of the current frame using thesub-pixel interpolation mode, to obtain a corresponding target referenceframe; and encode the current frame according to the target referenceframe, to obtain encoded data corresponding to the current frame. 19.The apparatus according to claim 18, wherein the processor, whenexecuting the computer readable instructions to cause the apparatus toprocess the reference frame to obtain the corresponding target referenceframe is configured to cause the apparatus to: acquire motion estimationpixel precision corresponding to the current frame; and process thereference frame according to the resolution information of the currentframe and the motion estimation pixel precision using the sub-pixelinterpolation mode, to obtain the corresponding target reference frame.20. The apparatus according to claim 19, wherein the processor, whenexecuting the computer readable instructions to cause the apparatus toprocess the reference frame according to the resolution information ofthe current frame and the motion estimation pixel precision using thesub-pixel interpolation mode, to obtain the corresponding targetreference frame is configured to cause the apparatus to: when thesub-pixel interpolation mode is a sampled sub-pixel interpolation modeand a resolution indicated by the resolution information of the currentframe is less than a resolution of the reference frame: performdown-sampling processing on the reference frame according to theresolution information of the current frame to obtain an intermediatereference frame; and perform sub-pixel interpolation processing on theintermediate reference frame according to the motion estimation pixelprecision, to obtain the corresponding target reference frame.